I haven't had a problem with that (using Linksys).
Right now we have (2) W2k Pro machines, (1) XP Home machine, (1) XP Pro machine, (1)Vista home machine and (1) Ubuntu Linux machine running fine on a router and switch.
For the most part, it was "plug and play".
I just went through some more issue, when I switched to wireless N. The router is supposed to run all three possible network security protocols simultaneously, but it does not like it much. What it does, is use a lower range antenna which affects the newer "N" speed improvements.
This caused me to upgrade my modems, and put some on ethernet. I have nine on the network in a single family home......LOL....