If you are just starting out then it will benefit you to visit the vidoes section in the learn area of this site. The following link leads to a basic video on asp.net's membership utility. It does all of the coding for you, and after a little head scratching works very well.

http://www.asp.net/learn/videos/video-45.aspx 

This video will more thoroughly explain how to set up the sql database that the embership utility uses:

http://www.asp.net/learn/videos/video-148.aspx

Good luck