SATA drives, whil using different connectors, are the same size and use the same mounting holes as a standard PATA drive.
My only suggestion would be to make sure that you get/have a model that supports SATA natively. I try to avoid using the PCI slot in those if I can avoid it, as it's cramped around the video card anyways, and taking up that slot helps reduce the airflow around the agp card. Was looking at several this week though that supported SATA, had connectors on the board, and even came with the required power adapter, if memory serves.