You CAN access internet content, though? You do get on AIM on your PocketPC and stream internet radio? It sounds to me like there is something wrong with PIE. Maybe upgrading the ROM would be a good idea.
[edit] Nevermind (see aim conversation)
Now it sounds to me like it's not routing port 80 information to your PocketPC. Try putting your PocketPC's IP address in the DMZ, Demilitarized Zone. And try, if there is a setting, to force data coming in on port 80 to go to your PocketPC's IP Address
[edit] Nevermind again (see second conversation)
Now it sound again like there is somethign wrong with your PocketPC. I'd suggest a hardreset. since you say you can get on on other routers but still not PIE.