You need a RAID controller chip or card in order to have RAID. (We wont' get into Windows RAID, people!)
Older enthusiast motherboards (two-four years old) would have the two normal IDE channels running off the motherboard chipset; two IDE channels can support FOUR IDE devices.
They would also have an additional chipset (typically VIA) that would support another two IDE channels (four devices) but with the added capability of RAID 0 or RAID 1. The chipset itself must support the RAID functionality.
If you want to get your feet wet with IDE RAID, get a $20 IDE RAID PCI card from Newegg (or the store of your choice), two IDENTICAL IDE drives (same manufacturer, drive size, etc) and go for it.
I have had great luck for the past 8 years with a 3Ware 7000-2 IDE RAID card, as well as using the onboard RAID of many motherboards.
"PC Enthusaist RAID" as I like to call it, is what most on these forums tinker with. Some of us also do this for a living and at work, maintain hundreds of SCSI drives running RAID 5/RAID 50 with tens of hotswap spares. It's great that it's not MY MONEY, b/c I could never afford it. LOL!
We're here to help. Go for it. Just remember this: RAID /= Backup. Put your OS/Games/video editing swapfile on the RAID array. Burn your pictures and other irreplaceable data to a CD/DVD and lock it up.