http://discussions.apple.com/thread.jspa?threadID=2478946&tstart=0
same thing during the first few weeks of AT&T's iphone 4 launch...... So give it a little time, and if your speeds don't improve in a few weeks, then complain
same thing during the first few weeks of AT&T's iphone 4 launch...... So give it a little time, and if your speeds don't improve in a few weeks, then complain