iPhonefreak

Well, as many of you know, today (March 6,2008) Apple. Inc released the software development kit (SDK) for the iPhone.  For those of you who do not know what the SDK is, it is a utility developed (and released)
by Apple that allows the user to create applications for the iPhone, and either distribute them privately (independently of Apple), or to have Apple distribute
the application via the iTunes Store and take 30% of the profit.

Here’s the difference: when downloading the free Software Development Kit from Apple, what you are downloading is the bare minimum application-set
(distribution via Apple Inc. not included). Basically this means that applications such as Xcode IDE, instruments, iPhone simulator, frameworks and samples, compilers, and the shark analysis tool are all included in the free package. Unfortunately,
being the free version, you can only run your developed application(s) in a simulator (to test functionality), but you cannot actually run it straight from the iPhone.

In buying the $99.00 standard program (or the $299.00
enterprise program), in addition to receiving the application-set (as included in the free SDK), you are also receiving iTunes Store “shelf space”. By “shelf
space” I mean that Apple will publicly host your iPhone application on the iTunes Store, and allow consumers to buy it directly from Apple (as opposed to downloading it from a privately owned website).

There is one downside to having Apple host your application, Apple is entitled to 30% of your total profits (in some cases this may not even be a downside because popularity of being on the iTunes Store + profit may outweigh the 30%  taken by Apple). Unlike the free
version, the standard program has many added benefits, in addition to having the ability to actually run your application straight from your iPhone (not only in simulator), you can also distribute it privately, gain access to pre-release software, get technical support, and various other features not included in the free version.

As of right now, one must apply to the iPhone developer program (if I understand correctly it is in "beta"), I am also under the impression that you will need to apply for the developer program until June, at which point anybody will be able to pay the fees ($99.00 or $299.00) and gain access to the developer program.