I am running Debian Woody with 2.4.27-2-686, and am trying to get the internal NIC to install
Good news: it should work..

Have a look at this article:
http://www.riedmann.it/linux/debian3smartarray.htmWhat you should do is, get the kernel-source of your kernel (you need 2.4.21 at least..), configure this one, and find the broadcom gigabit support, you should compile the support for this one as a module.. lspci should give you the info on the broadcom. I think the module is called b44.
After compiling the modules and making sure the broadcom module exists, you should be able to modprobe it.
I don't know your level of experience so don't worry to throw another question at it

And keep us posted..