It ain't nothin but a thing, man.
Start reading the classifieds today, or if your local paper has a day when they run alot more 'help wanted' ads, start there (here it's Wed and Fri classifieds for lots of help wanted posts).
Shine up that resume, have someone proof read and critique it. Get some internet advice on putting together a good resume and cover letters. Once it's ready, send it out to lots of places ASAP. Wake up at 0800 every morning and get ready to call the classifieds that look good, fax your resume out, etc.
Start cutting expenses now...save extra cash as a between-jobs cushion, because unemployment benefits aren't. If things get really bad, Wal-Mart or the local coffee shop will probably hand you a job in less than a week. It won't meet all your expenses likely, but it will slow the hemmorage until you find a REAL job.
You probably don't need any of this advice anyway. Like another poster said, there's always someone out there that need someone of any age to get something done. At my job they just hired a guy 3x my age (at least he looks that old) to replace a guy 1/3 his age to do an electronics job.
Remember: Getting fired is just an opportunity to find a better job.