There are a couple of applications that expand your abbreviations: TypeIt4Me, TextExpander, Typinator, etc.
I tried all of them and decided recently on TypeIt4Me. It’s faster than the others and allows me to stroke TAB as trigger.
TypeIt4Me at MacUpdate
Anyway, in case anyone is interested MacZOT has is for 37% less today:
Promotion: TypeIt4Me at MacZOT
I decided on TypeIt4Me as well. It seemed to give the most flexibility for my needs. I also have Textpander but haven’t used it for some time. I use Typinator for one thing–to expand two dashes into em dashes across programs (though I turn it off in Scr. because I like the way Scr. does it better).
I’ve been using Spell Catcher for that. It’s a matter of personal preference, I guess. They all seem to do the same thing.