the setup wizard on both machines.
Make sure that both machines are configured with the same workgroup name - MSHOME is offered as a default - and that both machines have a different name.
A common complaint by network novices is that the machines can't see one another on the network, and one of the most common causes is personal firewalls not being configured to allow traffic both ways.
Once you've completed the hardware installation, run the WindowsXP networking wizard on both machines. Make sure you have enabled sharing on any folders or drives that you want to access, although as a general networking rule it's not a good idea to share the root of a drive. In a home environment this doesn't really matter, unless you plan to share an internet connection between the computers - in that situation you're taking a risk if you enable sharing for the root of the C drive for instance.
Good luck - you know where to come if you hit problems.