iTunes sync over wifi is a commonly requested feature which should perhaps have already been implemented into the iPhone OS by Apple. However, it has recently been implemented by a developer to remotely sync photos, music and applications with your iTunes PC/Mac.
This video on YouTube shows the developed application working, it appears to some how emulate a USB connection across WiFi. iPhoneConnection suspect that Apple may already be working on this technology, or may even adapt this funcality as they previously have done with other Apple features (for example, Coverflow).
According to sources, the developer is to submit his application to the app store for review next week.