Rather than start another thread, I'll just add this here.
Much the same situation, 1950's house w/ no insulation in the walls. It's on the "gotta do it" list, and I know the first step needs to be closing all gaps, eliminating any airleaks (so I'm not blowing umpteen bags up into the attic or crawlspace ) but I've never used this stuff before. When I balance the cost of having it done vs the learning curve + frustration, etc, it seems like a no brainer.
So, what are the really useful things that a total naif wouldn't know about doing this?