Gray Cloud

hi
I want to Migrate exchange server 2003 front end/back end server to exchange
server 2003 cluster. My current setup is:
1) Exchange server 2003 ent sp2 front end server.
2) Exchange server 2003 ent sp2 back end server.

Now I want to configure cluster for my exchange. How I can do this without
affecting my users. I already purchased 2 new server hardware and storage. I
know how configure clustering.