I have done a lot of searching and come up empty on this.
I did see some advice that a radiator repair shop would be able to do it, but have not tried that route.
Here is what I did with mine...a presto 22qt caner.
First, make sure you have the original weight or a replacement from the company.
These weights are set to "jiggle" at 15 lbs.
Set up your caner with 3 quarts of water and seal it up.
Let the steam vent for 10 minutes and put the weight on.
As the pressure rises, the guage will move until the weight is jiggling.
At this point, the guage will stop moving and you are at 15 lbs, no mater what the guage reads.
Note the pressure indicated on the guage and adjust accordingly.
For instance, mine stopped moving at 13 lbs, meaning my guage was 2 lbs low...
If I want 11 lbs, I simply make sure the guage reads 9 lbs.
One piece of advice, if the guage is off by more than 2 lbs either direction, get it replaced.
Hope this helps, and remember, always check your home canned food BEFORE you eat it!

Thanks... That was helpfull ... how do you check your home canned food before eating it? Feed it to neighbors dog first, just kidding .

Here's a video that show how they test them - just for interest sake. http://www.youtube.com/watch?v=ejCsFKyZxUc

Always sniff or in my case - have someone else sniff - the contests of the jar. Check for bulging lids or anything else out of the ordinary. Back in the days before pressure canning when low acid foods were canned in a water bath the rule was: boil everything for 20 minutes before you eat it. The heat will kill the botulism spores and render the food safe. Please use proper canning techniques and approved recipes and do not can low acid foods in a water bath. 🙂

Much appreciated, I haven't used my preasure canner as I am a bit intimidated I will do something disasterous.

Syn, I picked up a couple of canning books (Bernardin is readily available and Ball is available in the US quite easily). Read through the instructions relating to altitude and timing and make sure your jars are nick-free, clean and are intended to be re-used. Some people use the Atlas jars that contain Classico pasta sauce and there have been failures as these jars don't take heat as well. Your jars should be hot when you fill them, and the lids should be placed in hot, not boiling water to soften the rubber to ensure a good seal. Don't preserve anything less than good quality meats and produce. You are spending a lot of time and effort to create a product worthy of storing and damaged produce may get you less than good results. One of my very first pressure canning products was Alaskan salmon canned at a campground in Valdez, Alaska so fresh, fresh, fresh. A drop of good olive oil and a dash of salt, if you want it, and some small salmon jars and the end results were so much better than any of the commercially available salmon. With some care and attention to cleanliness and preparation there is no reason to believe that your results will be disastrous, and I expect will exceed your expectations. Then you are on the way to delicious canned chicken, soups, relishes and salsas. And the bonus of all the pretty shiny jars full of wonderful flavours gleaming down from your shelves.