It is my understanding that the plastic bags used for frozen do not have BPA - it's usually used as a liner (to keep things from sticking) or for hard plastics like Nalgene bottles as a hardening agent. There were a few articles in our local paper last year and I'll try to find them but I did panic a bit last year before realizing that I could not control everything (I'm a bit of a control-freak). For example, I do a bean salad which is easy, nutritious, and DS eats - and I usually get the beans from cans. Open cans, dump in, add oil/vineager mix and serve. Now, I buy plastic bags and have to boil them all, so it adds a day to my prep time. We cannot afford to be buying all organic (though we buy as much as we can), or things like whole fresh tuna to replace canned, so we eat canned tuna in moderation now (it doesn't come in bags up here - which, of course, aren't recyclable anyways, so there's more guilt on that). And what am I supposed to do about refried beans? Do people really make their own? That's sort of a rhetorical question, but I have no idea how.
So, we try to avoid canned foods, choose more fresh or frozen, but we do eat them in moderation. I try to make the best choices I can, but we don't live in fear either. Also, I do remember hearing that highly acidic things like canned tomatoes had much higher BPA content than other things when tested. The heating thing is a big deal though.
I'll try to find those articles and post them, though maybe one of our scientists or Britonne2 will chime in