Another user here facing the same dilemma. I have dealt with this problem for about a year and figured it was just the result of 802.11 signal congestion. I faced all of the issues which have been described. When a black mac book connected to the network you might have an hour of two of web surfing and then you would get confronted with all these signal disconnect pages generated by the 2wire. When I moved to a new apartment there were far fewer 2wires and less signal congestion. So I decided it was another problem and not much to my surprise I came across this thread and tried to fix the problem.

Several step which I took

1. Had the line checked- no effect

2. Spoke with several at&t people and bounced around in several departments and none of them seemed willing to address the problem.

3. I was finally transferred over to the pay for it yourself tech support which I refused to do and was not told when the call was transferred that it would cost money. 

Then I decided to bridge the 2wire with an old linksys router. I was bounced around some more before I finally was connected to a level two tech who did a fair at best job of walking me through the steps to put the 2wire into full bridge mode. The website which helped the most was this one 

http://www.ehow.com/how_5160159_put-wire-bridge-mode.html

With the old linksys router with DHCP enabled, configured with the at&t login information, using WEP wireless encryption, I have been problem free for a whole day now. Im hoping this configuration is stable and I would probably recommend what other users have done to introduce a third party router.