Upgrading old network!

[CBR549]

I have a Windows 2000 system as a server and a windows 98 system as a workstation.
I have purchased two new Windows XP Pro systems and would like to change one out with the 98 and add the other one as a new station. what would be the most simple way to do this and is it very complicated?
Any assistance would be appreciated.
CBR549

 

[Death_Shadow]

Let me get this straight, you want to change it so your workstation is on XP and you're Server is still Windows 2000? Or do you wanna change both of them?