I submitted a BlackBerry phone version of the iTunes Sync program last night to App World. Although OS 6.0 and later devices get access to BB's WiFi Music Sync feature via the BlackBerry Desktop software, I sensed there might still be a market for the "one button" sync of my iTunes Sync app. (I'd personally rather do this than download a song or album at a time) Also, this sync works for OS 5.0 devices such as the Bold 9000 which I own.
I don't know whether RIM is allowing such applications that overlap build in BB features, so it will be interesting to see whether they approve it.