ATA-100 and SATA-150

I recently installed 3 WD Caviar SE SATA-150 drives. It was a surprise that the Serial ATA-150 interface required a separate controller and new cables. But that was my system so no problem when the delay came in ordering all the parts. Now, I have a client who wants to install a WD Caviar SE ATA-100 drive in his system. I have to admit, I have not kept up with the new drive formats. I don’t want to be embarrassed if this drive will require a new controller.

My question is: Is the new controller/cables only required with the SATA drives? Do regular IDE drive controllers handle drives with Ultra ATA-100 interfaces?