I have rhel5 as host ,and guest is xp and rhel5,how will I make a network between them .....

You need a physical connection. The cheapest and most available cards and cables are ethernet. You can find them in most computer shops. If your network is local only, buy a hub. A hub is cheap, has vary little or no logic. It is just a way to connect the cables.

If you want internet connectivity, or even a private IP network, you will need a router. Router vary a lot, some have wired ports, and some have wireless access points, for wireless communication. You need to define how you want to use the systems.

As for software, there are many ways to transfer files, share directories and files and share a printer(s). Once again, define what you want to do.

File sharing and printer sharing between linux and windoze requires a samba server to be installed and configured on linux. If all you need is files to be copied, the set linux as a FTP server.

I could provide a better answer if you define your needs and post them.

I've virtualized rhel5 and xp as guest on my host rhel5 with VMWARE.

Sorry I can help with Vmware. No experience at all.