1. Yes that motherboard has a RAID controller so you'll be able to do RAID0.
2. 2 x 250Gb is fine, however, I have found the performance of RAID0 to be ok, not exactly worth the hassle. I currently have 2 drives one with my OS and one for backups including an image of my OS drive so I can recover quickly.
3. There is a FAQ about setting up RAID0 on this site...... RAID FAQ
It's a little short on details but google will throw sometime up.