Apple has apparently boosted the maximum size of an iPhone app download over 3G from 10 MB to 20 MB. Previously, users who wanted to download an app larger than 10 MB had to switch to a WiFi connection.

The most obvious reason for the limit in the first place was likely to preserve bandwidth. However, many have speculate that Apple has made the change in anticipation of the iPad, which is set to debut in late March.

The thinking behind that is iPad application downloads will be larger than typical iPhone apps populating Apple’s App Store. Due to its 9.7-inch screen, iPad apps will have to support higher-resolutions graphics, especially for games. In the meantime, it appears iPhone users will be able to enjoy downloading larger apps while on the go using 3G.