There is a very detailed article on February 2005 issue of Dell Power Solutions magazine.
Configuring and Managing Software RAID with Red Hat Enterprise Linux 3
If for some reason the above link doesn't work anymore just go to www.dell.com/powersolutions
and navigate to Feb issue.
If the system is on a production environment, I have to agree with Thoreau, simply go for a tried and true hardware RAID controller
. Don't take me wrong, I think Linux software RAID is a mature solution, robust, and very easy on the budget. But it actually depends on what would be more expensive in your case.
Here is the why... Downtime cost money, and unless you have a full-time admin on-site software RAID means paying extra hours for someone to rebuild the array after replacing the defective hardware.
I myself am seriously considering a 3ware Escalade 7006-2 (PATA), which has the same controller and drivers as the 8006-2 (SATA), for my home file server. It is not that managing software based RAID is difficult, not at all... But less than US$200 (even less than $150 on-line) for a hardware-based solution is money well spend.
If you decide to go for a 3ware controller keep in mind that Escalade 8006-2 needs a full-length PCI or PCI-X slot, usually available only on enterprise class hardware, while the 7006-2 will fit on a regular PCI slot. In either case I recommend you go to shopper.cnet.com
and compare vendor's rating and price.