Promise Ultratx2 and cusl2-c, will these work together?

[init2winit]

ok got a great deal on this card, (free) can't beat that, but I don't know enough about this card to know if it will benefit me in my box, have Piii 1 gig on a cusl2-c, will this work or not? do I need a ata 100 or is this 66 bus speed ok?? Help!!! soo confused...