Vista Compatibility w/ XP Home Network

I also posted this question in the Laptop section as I am in the market for a Home/work laptop.

Question: Should I be able to access my home network (XP Prof, 2wire wireless DSL modem), with a laptop using Vista (home premium or ultimate)?

I ask because one of my son's friend's tried to access our network with his Vista based laptop and was unable to. I tried to help him connect, but the setup is different with Vista so I wasn't much help. I provided the number code on the bottom of my 2wire that I use to link my three home computers, but his computed would not accept that code (keep getting invalid code message). Were we doing something wrong or is Vista just not compatible with an XP network.

Sorry, The two numbers on the 2wire are its Serial # and Encryption key. The main computer is connected directly to the 2wire modem (Series 1000). The two other computers are connected through their wireless cards. I used the Encyption number to set up the adapters on these two computers.

My son's friend was trying to connect to my network using his wireless adapter, but his software would not accept the Encyption number we used. I think we rec'd a message that it didn't have the correct number of characters.