This was first supported on RHEL 3. The procedure to set it up is the same for RHEL 3 and 4. For newer versions of RHEL the procedure has changed a bit.
need to test this
iSCSI in RHEL5 and Newer
RHEL document Article ID: 34404
good document on how to setup iSCSI
Equallogic and RHEL 5 config