Daniel,
Yes I found the same thing myself... see how that curse works. So at the risk of ruining another solution (I've been "beep free for 2 days now wit this one) here's my most recent fix
I did more digging and found out on my Windows 7 system that Bonjour wasn't loading correctly through the Window's Event Viewer... anyway it turned out that my Norton Internet Security was being too aggressive in it's Firewall settings. So I dropped it down one notch and the beeps have gone away.
From other research I found that iTunes 11has many bugs and I believehow it handles Sync over WiFi is the culprit, even if you've turned it off. So until Apple fixes iTunes this little tweak to the Firewall has worked.... well up until I just posted this!
Hope this helps.... and I really hope Apple gets their software fixed. For a company that brags about reliability I find Apple is the worst at fixing these type of issues.
Bob