For those who are running Debian Lenny and want to order the new Dell R410 server, beware!
There is no safe solution to get Debian Lenny working with the on-board Broadcom network cards. A fairly recent kernel is required. Basically, you will have to install back-ported kernels, more recent modules and thus must violate the reasons why you were running Debian Lenny in the first place.
There is one solution, although it may not be an option: run VMware on the hardware and run Debian Lenny in a virtual machine. I think that in most cases, this will be sufficient for many cases and it has all the benefits of virtualisation and the stability of Debian Lenny.
It is unfortunate that Broadcom or Dell do not support Debian.
If you do have an easy and quite safe solution to get the Broadcom network cards working with Debian Lenny, please drop a note.
Beware though: the H200 and H700 RAID controllers are also not supported by Debian Lenny.