Cluster Servers?

OK, general server question...one of my friends is giving me a pair of Compaq CL380 cluster servers...I'm wanting to turn one into an Exchange server for sure, and possibly web server...the other I'm stuck between whether to use Linux or Windows 2000. I want to use it as a dedicated SQL server. Anyone have preferences? I'm used to Mandrake linux a little bit, and fairly used to Windows 2k server, but have never played with clustering before (this is going to be fun *gets maniacal grin*)...any tips for the "n00b"?

Depends on what kind of cluster. Beowulf?

A cluster is a group of computers running as one(parallel computing), so whatever os you choose will go on both. Typically a cluster would be used for huge computations, or load balancing/fault tolerance.
Here's a link on how to setup an apache cluster.

I'm looking for fault tolerance...I don't (yet) have needs for supercomputing. When I do, I'll build a mini-ITX cluster system.

Basically, what I'm getting, are two clusters. Each cluster has two dual PIII systems and a shared RAID array. One cluster will definitely get Windows 2000 Adv. Server or Windows 2003 server of some nature, and Exchange 2000 or 2003, possibly also IIS/PHP.

The other cluster, I was thinking of going Mandrake Linux, if mySQL supports clustering (or some other open-source SQL server)...mainly for fault tolerance reasons.

HOWEVER, since I really mainly want to use these two clusters for web serving (am setting my own hosting up), I was looking for recommendations as to whether I should use one as a dedicated web/email server, and one as dedicated database, or what combination of the services? I'm going to be offering FTP, SQL, Web, and Email services...just standard stuff. Clients don't need Exchange access I don't think; that was mainly for me to play around with. I could always keep the Exchange on another server I have, and just run Linux on both of the clusters.

Hope that makes more sense than my first post.