Today was a bit of poking around day. Tried to setup PXE booting from my FreeBSD 8. Didn't get it working using the guides (1, and 2 were particularly helpful) until I understood that the host setting (with MAC address) is really, really required. You can't have a setup where a PXE client boots something default.
After some playing was also able to get linux booting to work. Now installing Ubuntu 10.04 LTS on a Dell PowerEdge R210 using my new PXE boot capabilities.