If you still didn't solve your poblem,
You should have a look at page :
http://bugzilla.kernel.org/show_bug.cgi?id=2030
for your problem. It may help, and you should try, either an upgrade of the kernel to 2.6.6 or 2.6.8. Don't know much about this, except that I have some problems with an upgrade from kernel 2.4.20 to 2.6.2.
With V2.4.20, my Broadcom was ok on a direct internet connection, and it is ok when when used in a local netwok. I used the bcm4400 driver found on broadcom site. If you are interested, you can check a subject I started called "local network configure failed" in linux networking forum.
Hope it helps you, xround.