This sounds to me like it could well be related to the issues in this thread:
http://forum.vodafone.co.uk/index.php?showtopic=35483
My suggestion of changing the Registry MaxConnectionsPerServer helps mitigate (but not eliminate) the problem.
Another work-around you might also try is using Firefox and the "no-cache" headers add-in that many people on here swear by (tho I've not tried it myself yet, it does make sense).
For me, with IE7 and the MaxConnections hack, the homepage at
http://www.telegraph.co.uk/ still takes several
minutes (no exaggeration) to fully load via VF mobile broadband, despite my "raw bandwidth" for large files being around 1.2Mbps (143kBps).