Basic Explanation on Chipping?

I've looked at a lot site's that mention chipping. What I don't really understand as a newbie is at what areas of the short game do you use which club, and when do you shorten your backswing as opposed to not. I know you are supposed to open the stance, grip a little lower on the club and open the face when you chip. I guess basically what i'm asking is for an explanation about when to use the wedges and when to use the 7-9 irons. What is kinda confusing to me was I saw a video on the short chip, I gather from the fringe where the guy is using a 7 or 9 iron depending on hill slope. I would think thats a little different from your longer chip because from the close distance it's more like a putt.

Here is a link to my site and blurb on chipping:

http://members.shaw.ca/gord962/drills/chipping.htm

Chipping is the worst part of my game also. I must have read hundred's of articles on different methods of chipping. They vary from pros telling you to putt everything from 10ft off the green (having a clear path of course), or chipping only with a wedge using different length of back swing, to the more traditional, using a different lofted club for different distances and chipping only a few feet onto the green and allowing the ball too run to the hole.

What I'm trying to say, is that you need to feel comfortable chipping, with a method that suits your own style. The best place to learn is practice on the chipping green at the course. Get 100 practice balls and vary your methods until you find just the right one that works for you. Then practice some more. I still am, as I also haven't quite found the technique that suits me yet.

Cheers.
Lee.