What error messages are you getting? Also, have you run the network setup wizard but opted to NOT create a floppy?
A few things I usually do when setting up a network as well.
File and Print Sharing On - which you did so that's good.
Sharing of specific folders or files only on each machine.
Setting your firewall to allow the specific IP address (or range if you have multiple PCs) of the other PCs on your network for both machines.
Make sure both PCs have the same workgroup name. This is a common oversight.
Make sure both have permissions set in the user groups just in case. Usually not needed but I check it anyways.
Also, for networking Vista, you might want to check here:
Clicky