powerFlarm - FLARM und ADS-B has been announced. Their website is still German only.
What I like is that you will get alerts for ADS-B (Mode S) equipped a/c as well as Flarm equipped a/c. Helicopters use them too for cable and glider avoidance in mountanous terrain.
Think of PowerFlarm as a dirt cheap TCAS that will also warn you about gliders, especially as CAT is going to Mode S.