Hello everyone.
I have been having this same problem. Not only with iTunes Wifi Sync feature included in iOS 5, but also with the Apple-created "Remote" app from the App Store used to control iTunes via Home Sharing and ALSO with the Bonjour-enabled "AirPrint for Windows" service which I have installed.
For each of these apps, my iPad simply behaves as if it can't SEE the service on my PC (windows 7 x64). Naturally, each app has been configured 100% per the documentation included, but still my iPad just can't see the services out there. I feel that when I solve one of these issues, then the others will also be solved.
I factory reset the iPad and the router, and I reformatted my PC. Clean slate! This did not help, however. The network tools app on my iPad can ping my PCs IP address all day long, so I know it's not a simple connectivity issue. It must be a protocol or port issue.
The best guess that I have at this point, and the procedure that I will try when I get home, is one that I saw on another discussion thread here at Apple.com. Basically:
1. Access home router's config page via browser
2. Notice the UPnP setting. It is probably turned on. I know mine is at home.
3. Disable UPnP. Reboot router. Then go re-enable it.
This procedure has been said to work on the other thread. I hope to have good results tonight, and I hope that readers of this thread also have good results with this fix. Good luck out there!
Reference: hikerpa's post here: https://discussions.apple.com/thread/3375125?answerId=16337991022#16337991022
Message was edited by: KurtYoungWA