I have a 6800 and I also have had the experience of the phone freezing during WAP sessions. It might have to do with the loading of large pages in WAP. I'm no expert so I'm not sure.
*Funny thing, while writing that last paragraph, I was scrolling through my ringtones and my phone just froze. It never unfroze and I couldn't power it off so I just had to remove the battery and replace it and power it back on and now it's working normally again. STRANGE?!