ipw4945 maybe? The wireless stack in the kernel has been rewritten recently, meaning more common stuff goes into the kernel, and the code for each driver becomes smaller. This is a good thing, long term. But it's also a transition period and I have had plenty of weirdness with my ipw3945 (or iwl3945 as the new driver is called), a card that comes with most Intel based laptops. Even on 2.6.27-10 I still get disconnected from the network for no apparent reason now and again. I'm guessing the wonky driver is the source of your problems here.
You can find out what card you have with lspci:
$ lspci | g -i network
Mine says:
04:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection (rev 02)
EDIT: kudos