1. The computer will see it as a SCSI controller - no problem.. just set your BIOS to boot from SCSI after you install the card.
2. You will want a card that has the Promise S150 chipset (NOT Sata II 150). It is the most reliable and compatible and also has drivers for Win9x.
3. Even if only using a single drive, you will need to go into the card's BIOS and set up an array and initialize it.

Thanks! That’s really helpful, for some reason I can’t seem to find any information at all on these, don’t know if I’m searching for the wrong things or not.

Tried to find a spare IDE drive to put in there for now, which highlighted how much I could do with sorting out a SATA solution when I have time... out of a pile of 20+ drives I’ve had hanging around, from a job lot, I found 1 that wasn’t dying according to SMART or throwing up bad clusters. I’d hoped that they’d been removed from machines due to upgrades, or when the machine was scrapped, but no, looks like they might have all just been faulty 🙁

The only problem I always found with PCI SATA cards is that I never got to boot from a dvd drive connected to it, only hard disk. I don't know if it's a bios problem or whatever.
Actually I'm using the Fastrack 2300 PCI but with Linux.