You have 2 x UDMA ATA 133/100/66 Bus Master IDE ports
2 drives can be connected to each port.
This means that you can have a total of 4 drives connected.
A combination of hard drives and DVD/CD drives etc.
Don't count the floppy if you have one of those since those use a different port.
You need to get IDE drives, your motherboard does not support any sata.
I'm not even sure if they make 500GB drives for ide. You'll have to look around for there biggest size.
I'm not sure if you need to partition or not.
Also, most people here prefer to get western digital or seagate brands. After some quick looking around, they do make 500GB ones for ide.