You've actually come to a great place to learn knitting already - right here on knitting help!
Up at the top of the site you'll see various categories like "Home", "Shop", "Patterns", etc.
Go to the one marked "View Videos" and put your cursor on it. There's a great section there on "getting started" and it will give you a neat push in the right direction. All you really need is some yarn (almost any type) and a pair of knitting needles. I'd suggest maybe an acrylic cheapie yarn with about a US size #8 or #9 straight needles. But see what Amy recommends in the videos.
There have been many folks who have learned to knit directly from this site, with the help of the other knitters in the forum. If nothing else, you'll be a little less mystified when you go for your class at JoAnne's!
Please let us know how it's going for you and write in if you have any questions meanwhile.