Can you use an iPhone in Internet marketing? If you spend any time on the road, the answer is a resounding yes.

With a mind boggling 140,000 apps that run on the iPhone, the device has gone from being a mere cell phone to "your computer away from the computer." You can surf the web in brilliant detail using a version of Safari that works much like the Safari on your Mac, check up on your sales totals for the month, create to-do lists for the coming days and weeks, read and send e-mail from the same accounts as you use on your Mac, check up on the success of your current Web campaign, and more.

The iPhone has achieved a stunning success in the smart phone marketplace for a reason: it brings Apple's  quality of workmanship, smoothness and brilliant interface design to the smart phone.

In fact, millions of people who would never think of purchasing a Mac because they are locked into the PC mindset have giddily embraced the iPhone. The iPhone (and iPod) was Apple's brilliant "foot in the door" that got many PC users to consider the Apple product line. PC users could enjoy Apple’s quality of engineering without the hassle of learning a new computer system and transferring all their files over. In fact, many PC snobs who looked down on the Macintosh have become some of the foremost proponents of the iPod and iPhone line.

In many ways, the iPhone is like a "Mac in your pocket." It embodies the same stunning quality of engineering and brilliantly well-thought-out interface of the Macintosh. All in a package you can carry in your pocket or hold in the palm of your hand.

Following is a tiny selection of the available iPhone apps that can be of use to Internet marketers.

Action Lists

Creating to-do lists and goals is an important daily activity for any successful business person. Action Lists is one of many to-do list managers available for the iPhone. It is an app that seems simple at first glance but reveals an impressive amount of depth once you start exploring it.

The main screen contains a list of the current to-do lists that you have set. Tapping any one of these items brings up the task details screen in which you can assign the task to a project, set the context, assign a start and due date, set repeat options, add notes, and more. Buttons visible at the bottom of the screen provide quick links to available options.

Roambi

Roambi (pronounced roam-bee) is the slickest, smoothest app for the iPhone I have found to date. It is essentially a spreadsheet program, but, rather then trying to shrink down a standard computer spreadsheet to the iPhone screen, it instead reconfigures the way the data is displayed. It can display data as a stack of cards in a card file, as a catalog of line charts, as a simple interactive pie chart  or as a detailed "super list" showing bar graphs for an extensive list of items.

Roambi doesn't simply show a scaled-down subset of your spreadsheet data; instead, it totally reconfigures it to perfectly fit the iPhone screen and capabilities. In a Roambi data view, all of the information in a large spreadsheet is accessible, but reformatted in such a way that it is not only accessible but actually kind of beautiful.

AmbiScience Brain Power

Sometimes when you're on the road you simply want to drown out the hubbub and noise around you. AmbiScience Brain Power can help. It plays a number of soothing sounds that, with headphones, can help you concentrate. The app claims to "sync your brain waves which leaves you feeling refreshed, peaceful and inspired." I don't know about that, but I do know that this app is a good way to drown out extraneous sounds.

Aji Reader

Aji Reader is an app that allows you to—get this—view full-sized PDF files on your iPhone. Simply enter in the URL at which the PDF that you wish to view is found on the Web and it will be downloaded to your device. Viewing a PDF formatted for 8.5 x 11 paper on the 2 x 3" screen can sometimes be a challenge, but landscape mode and the high-resolution of the iPhone screen helps. The app has quite a bit of depth and itself has a 36-page user manual (in PDF format, of course). 

(Note: Apple's new iBooks app also lets you view PDFs on your iPhone.)

ThinkingMap

Since we rarely think in a linear fashion, and one thought often leads to another in an (hopefully) endless fashion, the mind map as been developed to help us capture our thoughts.

Most people think of using a mind map on a large screen, but a number of mind map programs have been developed for the iPhone. If you're on the go and you find yourself with some spare time when a brilliant inspiration hits you, it can be handy to have this in your pocket.

ThinkingMap displays a simple black-and-white mind map that effectively takes advantage of the small screen real estate (but does not allow you to move or rearrange topics once you have created them).

SimpleMind

This mind map app offers a more colorful but somewhat less space efficient interface that does allow you to move subtopics around By dragging them with your finger (but does not seem to let you reconnect a subtopic to a different topic if you decide it fits better somewhere else). Both apps let you export your mind map as an image that can be much larger than the iphone's screen, although SimpleMind offers higher resolution.

Analytics Agent

If you have a spare moment while on the road, why not check up on how your websites are doing? Analytics Agent allows you to access your Google Analytics data through a slick, easy to use interface; just enter your analytics login information and connect!

This is not merely a web page shrunk down to iPhone size. Instead, the analytics data in the form of lists, bar graphs, pie charts and more is reformatted to smoothly fit the iPhone screen. Buttons at the bottom of the interface allow you to view the total number of visits, the number of unique visitors, the page views, the amount of time visitors spend on the site and the bounce rate (the percentage of visitors who view more than just the home page). This app comes in both a free and a paid version. The free version displays ads while the paid version contains more info. Analytics Agent should not be confused with an inferior app simply called Analytics with which I have experienced intractable login difficulties.

Twitter

Twitter is the micro-blogging platform of the year (or maybe the decade), and it is just as popular with Internet marketers as with the general public. The iPhone is a great vehicle to let you keep in touch with your Twitter followers, as it provides access to the service at any time of day, wherever you may happen to be.

Apple’s app store lists dozens of Twitter apps for the iPhone, including one provided by Twitter itself, called simply "Twitter" (although some screens are labelled "twittermobile." It offers real-time search, Top Tweets, trending topics and maps that show what’s happening nearby or across the country.

Got a free moment? Update your Twitter feed, or catch up on the general Twitter stream. Your Twitter account need never be stagnant with Twitter installed on your iPhone.