Install Windows 2000, then install XP in a different folder or partition. The built-in boot loader will set up a boot menu automagically for you.

what like c:\windows2 ?

would having on same drive and partition cause problems?

C:\Windows2 or whatever is fine... You can install to the same drive, but I would recommend against it, as there could be some file location problems when programs are installed, etc.

I agree, use two partitions and the installation will do the rest for you!!! Very easy!!! 8)

I'll back that up.. split partitions! Partition magic will assist you on this if you don't know how to use fdisk. Also it maybe better than fdisk if you are planning to keep your current OS instead of doing the whole thing clean.