[ame=http://youtube.com/watch?v=u_09mqhMa-g]YouTube - Wi-Fi Sync for iPhone: Syncing music tracks with no USB cable[/ame]
It looks like the WiFi Sync app by Greg Hughes, which had previously been submitted to the App Store, has made it's way to Cydia. The app connects over a wifi network to a computer running the client app, and syncs your phone as if it were connected via USB, and is available on the BigBoss repo for $9.99.
While not officially supported, it does work on the iPad.
For iPad Installation.. Purchase on your iPhone first. Next.. open Cydia on your iPad and choose ANY Cydia store package.. click purchase... choose whichever method you use to sign in (Google or Amazon). After you've signed in hit cancel.. then go to WiFiSync and it should now have an "Install" button at the top instead of a "recheck" button
Currently the client app is mac only, but a version of the software compatible with Windows will be available shortly.