network with mac

I realise it's still in beta, but has anyone successfully managed to network windows 7 with mac osx 10.5? I can see the aspire one from my imac, but not the other way round.

When I installed win 7 I had a choice of network options, I chose 'Home' (or something like that) that I've since found uses the new Homegroup feature. perhaps this is blocking me. I've turned homegroup off (I think I have anyway) but I still can't see the mac. Under XP and Vista I literally just go to network and browse and up it pops.

Update, just worked out how to change home to work network, but still no joy....hmmm.....