According to the apple website iOS 4 should support wireless app distribution. I have been unable to find any documentation at all on how to host your applications for users to download them over wifi/3g.
We are currently enrolled in the standard iPhone dev program, as we don't have over 500 employees. Is this limited feature limited to the enterprise program only?
If you don't have an entreprise account. You won't have the unlimited or very large pool of devices you can add to your account distribution profiles. BUT, even with normal accounts you can definitely create an Ad Hoc distribution profile (limited to 100 devices) and use the Xcode 3.2.3 "Build and archive" + "Share app / Distribute for entreprise" feature. This will create a .IPA app bundle that already contains the distribution profile. All you need to do is create a web page on some server containing a link with some special scheme.
For instance:
<a href="itms-services://?action=download-manifest&url=http://www.myserver.com/ota/myapp/appname.plist">Install My App over the air</a>
Found a guide on how to get wireless app distribution working. You do not need to be part of the enterprise program for this to work.
http://jeffreysambells.com/posts/2010/06/22/ios-wireless-app-distribution/
The official documentation is no longer tagged as pre-release (and no longer requires a dev login):
Hockey is a really useful project for wireless app distribution. It has all the server side ready to make it easy to distribute the apps. It also contains an iOS module that can be used to auto-update the apps.
Source here: https://github.com/TheRealKerni/HockeyKit
Fire up Xcode and select Build -> Build and Archive. The Organiser will pop-up. Select the build you want to publish and click on the Share... button above the list. Select then the identity you want to sign your code with (usually this is the same you use for signing the code for a standard deploy on the device). Click, then, on Distribuite for Enterprise..
At this point a form will appear asking you from which URL the application should be downloaded from. Let’s suppose your website is available at www.example.com and your application (the file .ipa) is hosted at www.example.com/download/myapp.ipa, then http://www.example.com/download/myapp.ipa should go in that field. [See the update below] Fill the other fields as you wish; you can get more information about that in the Apple Documentation
Once you filled the form and clicked OK select the place where to save the generated files (ipa and plist).
Now the tricky parts comes when you have to deal with the webserver-side code. I have created a small example page below. Remember that you have to put on your website all the files: myapp.ipa, myapp.plist and myapp.mobileprovision.
<!DOCTYPE HTML>
<html>
<head>
<title>Install your application</title>
</head>
<body>
<ul>
<li> <a href="http://www.example.com/download/myapp.mobileprovision">Install Team Provisioning File</a></li>
<li><a href="itms-services://?action=download-manifest&url=http%3A%2F%2Fwww.example.com%2Fdownload%2Fmyapp.plist">Install Application</a></li>
</ul>
</div>
</body>
</html>
Please notice that the second href is nothing just a plain old-fashioned URL. Nothing special into that. If you are wondering about those weird %2F and %3A they are normal urlencoded symbols (for ‘/’ and ‘:’ resp.). Once you did this you are definitely done.
This answer has been taken as part of a blogpost I made in 2010. You can read the full story here
More info directly from Apple at: http://developer.apple.com/iphone/library/featuredarticles/FA_Wireless_Enterprise_App_Distribution/Introduction/Introduction.html
Apple Developer account required.
