I found GPRS activity of my 3GS 4.3.3 (jailbroken) at night (at 03-05AM) for about 600-700 kbytes every 5 - 12 days.

I've installed tcpdump and found that it sends HTTP request to http://itunes.com/version, than downloads large XML file (with somekind of settings and firmware urls).

In HTTP headers I found the user-agent line:
CommCenterMobileHelper/1100.16 CFNetwork/485.13.9 Darwin/11.0.0

Sometimes it tryes to GET this URL:

Than ends up with:

HTTP/1.1 302 Moved Temporarily
Location: http://ax.init.itunes.apple.com/WebObjects...dsid=1038321339

Any ideas how to get rid of that hidden internet activity?
May be removing the /System/Library/LaunchDaemons/com.apple.CommCenterMobileHelper.plist will help?