Apple increases OTA download limit to 50MB
For quite a while now, the limit for iTunes downloads on a mobile signal (not WiFi) had been 20MB, but it looks like newly released iOS 5.1 will be increasing that limit. Now, users on iOS 5.1 will be able to download files up to 50MB from iTunes over 3G/LTE (depending on your device). That should cover most anything you'd want to download except for video and some larger games.
source: The Verge