Running a raid array?
 

I am considering buying 2 identical sata drives to run a raid array. I would like to be able to mirror the information because I have lots of important information that is updated constantly during the day.

What kind of controller do I need to buy? How hard is it to configure? How much speed will I gain in data access?

Also can I use my current drive, 160gb sata, and match it with a similar sata hard drive? 200gb, 250gb or whatever is on sale??

Concerning your first two questions:

You need to know what kind of motherboard is running the system first and foremost. If you're setting up a new system you want a mother where RAID is integrated so you don't need a controller at all.

Sounds like you're looking to setup RAID 1 to mirror the data. You'll gain no speed in this setup.

You can use two different size drives but RAID is only as good as the smallest drives. In an ideal setup you would want two identical drives.

Do yourself a favor and read up on the basics. It's not complicated at all.

yup, yup and yup.

your 160 matched with a 200 will only give you 160 G usable. mirroring doesn't really offer speed improvements, just disk loss protection.