There are drivers that aren't in the official kernel, some distributions (probably Mandrake atleast) apply them so they should work out of the box.
The problem before was that it's not real RAID, all the RAID is done in the driver so Linux people just use the Linux software RAID (md or lvm) because it has similar, sometimes better, performance and the manufacturers wouldn't publish the semantics they used to disceren between RAID volumes and regular disks but I believe most have been figured out, atleast the HPT and Promise ones anyway.