This is, at the moment, useful only to developers with a paid account. Buried deep in Apple documentation, and only available on iOS4 Apple now allows developers to install their apps over the air for ad-hoc distribution and/or beta testing. These apps still need a signature, and you have to have a server to host them on. You’ll need to write a little index.html file as well. Follow along:
In xCode you need to build your app from the build tab select “Build and Archive” this is the accessible from the organizer window.
You will then “Share Application” via Enterprise. Fill out the exact paths to where you will host the app including the “app.ipa”
Now, choose the where you want to host your app, in order to share it ( i.e http://yoursite.com/yourfolder/yourapp.ipa )
xcode will save the app as an ipa and plist. You’ll need to upload these along with the provisioning profile the app is signed with to your server, following the path you gave earlier.
Now to write a little html index that you’ll need in that same folder, so your users have something to click on.
I did it in TextWrangler, but use what ever you’re comfortable with. Save it as index.html, and put it in the same folder on your server.
Now give your testers the address to the folder, to visit via mobile safari and all they have to do is tap both links, first installing the provisioning profile, then the app.