This may not be a notebook problem per se, but I am using one. I have a black Macbook 2.4 GHz, about 6 months old. Recently (3 months ago) it started dropping wireless connections. It will be working fine, but will all of a sudden have the menubar airport gauge from full to maybe 1 line (out of 3). It's lost the network at that point. It happens with multiple routers. Set up in different ways. I've tried keeping the wireless channel constant, but that doesn't seem to help either.
To solve the problem, I turn off/on the Airport card. Picks up the network then, but in 3-10 minutes, it goes down again.
Any ideas? Bad airport card maybe? It's only an annoyance when I have to keep and hold a connection without interruption. Most programs handle connection interruptions fine, but others not so much!