Just to clear up some of those questions. I ordered this card from newegg and installed it on my Dell 4550 that is running XP Pro. I did a Ghost backup to a network drive of my WinXP 40 GB disk, ran the RAID card array configuration, then ran the Ghost restore from the mapped drive to a new 80GB RAID 0 array. One of those 40GB disks is a Maxtor, the other a WD. I had just one 40 GB partition before, now I have a 15 GB one for Windows XP and whatever misc stuff gets left on the C: drive, and a 65 GB data partition for applications and the rest. It booted with no problem. I do see better start up times in games, and things that do a lot of hard drive access like loading a couple thousand song Winamp playlist with ID3 tags set to read on load. I've got another 120GB drive coming in to pair up with an existing one that i have, maybe i will do a RAID 1 with that, haven't decided yet.
I was also wondering if the RAID function of the card is useable in linux, or just using it as an additional ide controller (Which I do know is supported, I've just seen no documentation on the RAID part).
So far, I'm pretty happy with it. (Kind of a pain to set up though, having to use Ghost for the first time and find a boot disk online that would work with the Dell 4550 Intel Pro 100 VE network card, and doing all this after I pretty recently reformatted and reinstalled XP.)