I have a network with mixed wireless and wired LAN.
Amongst other things I have 3 Windows machines on the network:

    Tim-Laptop - running Vista connected wirelessly
    FionaHG - running XP Pro SP2 connected wired
    Tim64FC - running XP Pro SP2 connected wired

All 3 machines have their workgroup set to RENUKAFARM
The wireless SSID (relevant as it appears in the network pictures below) is 33ChurchMeadow

I have downloaded and installed the network discovery service for XP recommended on the help to allow Vista to discover XP machines (on both XP machines).