Promise cards are pretty-much the standard for IDE RAID 0 and 1. If you have a promise Ultra66 (non-RAID IDE card) you may already have all you need. This card used to come with certain retail-boxed hard drives, so it is pretty common. Look here in case you're interested in converting this card to RAID.

Another note, you may not be into Linux but Promise chipsets are well supported. HighPoint based cards will not work as RAID cards in Linux last I checked.
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-Rob Riccardelli
80GB 16MB MK2 090000736