Just to update an earlier post:
Forming a government in Berlin seems to be the easy part of the process. Saxony and Schleswig-Holstein will also be getting Black-and-Yellow governments but in the other Länder, the picture is more complicated.
Brandenburg: Matthias Platzeck had the choice between Red-Red or Red-Black. Here it seems that the CDU blew it by not having secured the internal hierarchy. Die Linke, on the other hand, realised that Kerstin Kaiser was a no-no as a cabinet member (she worked as a Stasi-informer when she was a student) and declared that they will negotiate with the SPD but keep her outside the state government. Also: Going Red-Red would secure the SPD from attacks in a fiscally difficult situation.
Saarland: Here Die Linke (and Oskar Lafontaine in particular) is the big no-no. The Greens seem to be serious about entering a Black-Green-Yellow coalition. In German this is known as the Schwampel or Jamaika coalition.
Thüringen: Looks like a complete mess. The leader of the state SPD Christoph Matschie wants a grand coalition, the party base wants Red-Red-Green. CDU’s lead candidate Dieter Althaus was forced to resign following the election – the question now is if the SPD will also lose its lead candidate.