Blimey, you've left it a bit late, haven't you? Mine expire next year and I was almost panicking that I wouldn't manage to use them, but after careful research I managed to use them on a series of upgrades which was a much better deal than using them as pure award tickets because of the high taxes on the latter. The call center agent was amazed, she said I was a total 'Seltenheit' because most people end up unable to use their miles. Airberlin has an excellent business class, I can really recommend it.

Remember if you're looking to book business on other carriers (eg AA) then you can't do it online, you have to phone the call center. If you speak German, the call center is excellent IME.