If the remote machine is not on a network that you are logged onto already then I dont think so.. the IP is the correct way of finding it.
Is the machine at another location, or on the same network in the same building?
Rather than faf around with this I have taken to using logmein.com There is a free version for home use which I find very handy for logging into my dads PC 130miles away. You do need to get a snipet of software downloaded onto it first though.
There is also Hamatchi, which is a little different but essentially sets up the network protocols for you. A bit like ICQ, or Messenger for the linking.
Personally I use these, because I dont trust the XP security and having worked in a few IT companies (I'm not IT I was installing electrical stuff) quite alot of them used Logmein's services as a trusted remote access.
Hopefully this will help a little... Or more Mac - XP knowledgeable people will give you the proper spiel.
Wheaty