SATA Drive Question

I am old school and have used IDE for my rigs up to this point. I might order a new hard drive and I had a few questions regarding SATA setups.

Currently I have 3 hard drives and a DVD/CD RW. They all currently utilize IDE. I am not certain if any are SATA capable. I will check when and if I order a new drive and make changes accordingly.

If I order another drive can I just throw it in and connect it via SATA to the MB? Or can I only use one interface or the other? I might need to do this in case my old drives are not SATA capable. If they are, do SATA cables daisy chain? Or is it one drive per cable?

The computer in question is an AMD 64 4000, 2 gigs of DDR RAM, ASUS AN8-E MB running up-to-date WinXP.

Thanks for any responses.