The sweater wizard does let you do that. It seems very cool. You can get more info on this site: http://www.software4knitting.com/psw...zard/pswiz.htm
Looks like you can do everything you can imagine, etc. I am sure its not as easy as it looks, but I am considering it!
They also have a sock wizard that you just put the shoe size in and viola! It spits out the pattern based on your gauge, yarn, etc. Pretty cool. I just haven't knit socks yet.