I am attempting to add my new Snow Leopard MacBook to an Active Directory domain and I had a little trouble finding how too. The first thing I wanted to do was to change the computer name.
After Googling the issue and finding no results, I decided I would post the solution when I discovered it:
To change your Computer name on Snow Leopard:
1) System Preferences -> Sharing
I also changed my WINS hostname at the same time so that they matched:
1) System Preferences -> Network -> Click Network Adapter (Airport or Ethernet) -> Advanced Button -> WINS
Enter your computer name, domain and wins server address in the relevant boxes.