nmblookup? What's it all about, and should I let it allow connections?

I think I'm posting this in the right area... if not, apologies!

Every so often, Leopards firewall wants to know if I want to let 'nmblookup' to allow incoming netowrk connections. I don't beleive this to be anything mysterious or bad - an internet search suggests this is part of the 'Samba suite', whatever that is...

For the moment, I've been clicking Deny, but in the future, what should I do?

Cheers in advance for thoughts and ideas.