my guess is that Firefox can't understand that you are connected, beacause GPRS is daln slow
(it's okey for phones).
and try this:
Code:
Go to about:config and search for network.dns.disableIPv6. Change the value to true and voila, the internet is now fast again.
http://www.davidcramer.net/other/77/slow-connections-in-firefox-3-beta-3-on-mac-os-x-leopard.html