where do you start?

It's so interesting that you posted this, because I'm mulling over how to get some strength training into my life. My choices are either long term gym memberships, joining a local community college's gym for $20/month, or hanging the TRX I bought last year up in my garage. I think the last two are my best choices.

You'd crack up at how many holes we've put in our ceiling trying to hang that TRX up there...it looks like someone put 15 holes up there in a circle around the bracket...oh, yeah, they did put 15 holes in the ceiling.

Back to your initial question, my suggestion would be to hire a personal trainer for a few sessions. If you've not done ST in a while, or ever, there are so many things they can teach you about form. I promise once you've learned it, you never forget. I had a trainer back in the 90's and I still remember the things she taught me about form and reps. They can guide you on which body parts to focus on, how to warmup and stretch and even guide with food intake if you'd like. Mine did and it was very helpful. I could probably stand to have a 'refresher' course...or just get my tail to a gym again!

Let me know how you're doing.

I know there are ways to start a cardio exercise routine. Runner's World's "Run Your Butt Off", C25k, etc. How or where do you start on strength training? I am not looking to be Hercules, just want to gain flexibility, build muscle.

Cardio and strength training are two very different things.
If you want to build muscle, get something like The New Rules of Lifting (amazon.com) and follow that as an introduction. Skip the cardio for now. I believe Allwyn (the author) reccommends HIIT about midway into the program for fat burning.
Steady-state cardiovascular exercise is a poor method of fat loss, as your body (and metabolism) quickly adapts to the exertion you place upon it in order to minimize energy expenditure. Unless you are training for endurance, a cardio program alone will not build muscle nor burn fat after the first week. You will end up on a plateau and frustrated.
The other component of building muscle is nutrition, NOT "dieting" or calorie reduction. As you build muscle, you need to feed them sufficiently or again, your body will try to conserve resources and slow its metabolism down.