It's a pain in the .... You can't book through the website, you have to call in. You can't see availability on ba.com, you have to use aa.com. But it's worth it, for short- and med-haul flights it's cheaper than using Alaska points.

Search the web, there are several blogger posts on how to do the booking. Don't forget to ask them to waive the phone booking fee (which they will always do).

Neil