It is free for the end user to sign up and use as a personal API (and we already have around 50 or so services). What we charge developers for is building multi-user applications on top of it.
If not, you can (eventually) use Personable.me, but I'm still in the process of integrating enough sources that one could realistically use for health analysis.
Sorry, yes, I should have qualified that. Yes, I'm building that. It's only about a week's worth of development thus far, but I've got a fitbit and a WiiThings scale on the way to start integrating those into the API as well.
edit: fwiw, I understand if it won't be.