I had a flat tire two weekends ago. It was a nail in my tire, so it was a slow leak. I put some air in it, and took it to the shop. They roughed up the inside, threw some goop on there, put a patch on, then threw some more goop over the patch.
Seems good so far..
From what I hear about the fix-a-flat stuff is that it only should be used as a TEMPORARY fix until you can get to a repair shop. Also, I think most of that stuff is flammable, and the repair shop has to be notified that the tire contains the fix-a-flat so they can vent the tire outside.
Riley