[dba-Tech] Advice on Consolidating Workgroups, Domain etc.

For various reasons (mostly my own stupidity, but also including other
reasons), my home network contains two workgroups. There are 6
computers, one of which is a server. Two PCs are running windows 2k, the
other PCs are running winXP, and the server is running win2k advanced
server. 

Workgroup 1 consists of Rock, Excalibur, Lancelot and Zappa.
Workgroup 2 consists of Avalon and Guinivere.

>From my main PC (Rock), I can see Zappa, a shared folder on Avalon, and
Excalibur. (To be accurate, I can see a shared folder on Avalon, and
that's all that's shared there. But when I click the "Computers near me"
icon, I can't see Avalon. Is that normal?) I cannot see Lancelot, which
runs XP and shares nothing, so I guess that makes sense. I cannot see
Guinivere at all, and only the shared folder on Avalon. These latter two
run win2k.

Ideally, I'd like to consolidate the two workgroups into one, or
possibly consolidate them into a domain and then lose the workgroups. As
you can gather, I know very little about networking and even less when
there are two OS'es involved.

Can anyone provide suggestions, advice, or even better a step-by-step
recipe for how to do this?

TIA,
Arthur