Here are two ways of attaching a can. The way it is done on the Ruger obviously requiers the muzzle to be re-crowned, and you loose a half inch or so of the effective barrel length. It's also important to actually use the protective nut when the can is not attached, otherwise the threads will fill up with dirt and lead particles.
I'm very happy with mine, the gun is not altered in any significant way when not suppressed. The long can at the end of the barrel changes the balance a bit, but it's surprisingly easy to shoot well. Accuracy does not suffer, nor does point of impact change on either of my guns, but strange things may happen when you attach all that weight at the muzzel.
The one on my Ruger was made by a local gunsmith years ago, I think I paid 120 dollars or so, including the threading of the muzzel. The can on the rifle (CZ) is mass produced, and I think all the rifles imported to this country are threaded as a matter of course, "no one" buys a .22 without a suppressor anyway. I paid about 350 dollars for the CZ complete with suppressor and a scope a couple of years ago. No tax stamp, no hassel, it's great to live in a civilized country.
You may also want to go here: http://guns.connect.fi/
There are some interesting stuff about suppressors among other things. Check out the link to Reflex suppressors.