Universal method to record calls via Bluetooth in OS X 10.6?
Returning to this question several years later, it's still a pretty sad state of affairs. The only reliable answer is some sort of hardware solution.

In practice, this is what I ended up buying:



http://www.amazon.co.uk/Olympus-TP-8-Telephone-Pick-Microphone/dp/B007OXMHDE/ref=sr_1_11?ie=UTF8&amp;qid=1400147804&amp;sr=8-11&amp;keywords=voice+recorder+microphone

It works really well; you connect the jack to a voice recorder and put the earbud in your ear, which has a microphone and sits between your ear and the phone's speaker. The quality isn't bad (albeit not broadcast quality) and the ability to use an external voice recorder means I'm not having to deal with moving files off my phone or expend extra battery power on a recording app.

That said, this looks really interesting (Though I'm unsure whether you just connect it to your phone and use normally, or whether you connect some sort of hands-free headset to the other side):



http://thenextweb.com/gadgets/2014/05/12/15-quirky-gadgets-accessories-buy-today-2/2/

Considering the question is ultimately about finding a cheap or free software-based recording solution, I'll leave it open in case anyone comes up with something workable.