How to setup Window 2003 Domain at home?

I am looking to setup a Windows 2003 domain in my home for testing.
I have a Windows 2003 server loaded.
My connection is Comcast that goes to a Linksys WRT320N that is currently handling DHCP and I also guess it is orwarded the DNS from the ISP. I have wired and wireless connections on the WRT320N I could not get my client machines to join the domain. I am sure it is an issue with the DNS and DHCP. Need assistance in finding a solution.