Try to change your DNS server settings. I had the same problem, found a post on another site recommending use of different name servers. Here's how:
Settings --> Wi-Fi
Tap the blue arrow next to your wireless network
Tap in the DNS text field and delete anything that's in there already
Now, enter the new name server IPs
There are a couple of options:
Google's public DNS: 8.8.8.8, 8.8.8.4
Open DNS: 208.67.222.222, 208.67.220.220
I currently use Google's name servers, but others might work better for you.
PS - you can do this on your iPhone, home computers, etc which might help "speed up" your Internet connection ( though it really isn't affecting the speed of your connection)
Enjoy!