I bought an el-cheapo universal laser bore sighting toy from wally world a couple of weeks ago and have used it on several rifles so far and, well it actually works. I sighted a couple of .22s, a 30-30 and an AR.

In every rifle I sighted I used a distance of about 40 feet in the back yard, and sitting at a picnic table. After I sighted the rifles, I took them to the range and every one was on the mark.

Pretty impressive for something that cost less than $50.00.

It is kind of like this one here, but a different brand name.

http://i2.tinypic.com/otdwya.jpg

I've seen the ones that are actually mock up cartriges with a laser in the tip, so when you chamber the round (laser) its pointing through  your barrel and down range. They're about 40 bucks; I've never tried them but was curious as to how well they worked.

I have the Laserlyte.  Works real good.

The downside is it uses oddball batteries.