Long ago, back when I first started this blog, I did a series of posts on playing a deadhand approach shot, a la Steve Stricker. You can still find that series listed on the Some Useful Post Series page.
However, the technique is useful for all manner of iron shots where you need accuracy. Here's a video from golftipsmag.com with a simple demonstration of a deadhanded wedge shot.
You control the length of the shot by the length of the swing and, if necessary, by choking down on the club.
The key here is keeping your wrists and forearms relaxed during the stroke. That's what allows you to get the cocking and uncocking action of the wrists consistent time after time... and that consistency is the source of your accuracy.
This is a simple shot that takes very little practice to learn but can really add some versatility to your game. If you don't know it yet, learn it now!