Windows XP shared printer

I have a printer connected directly to my Windows XP pro machine which is not
part of any domain (i.e. workgroup). I have a couple of vista machines
which are part of domains and would like them to connect to the shared
printer where everything is on the same lan and subnet. I was able to do
this when my vista machines were xp pro via ip address. I've tried this with
vista but it doesn't work.

What are my options?

Any insight would be greatly appreciated.

Thank you.