Blizzard and Valve have come to an agreement for use of the DOTA name, which was previously going to land in the courts but has now been settled between the two companies. Valve will continue to use the "DOTA 2" trademark and Blizzard DOTA will now be called Blizzard All-Stars. The DOTA trademark will still apparently be useable by fan maps (presumably for Starcraft 2) though.
Good news that this didn't end up in litigation. Blizzard and Valve are two of my favorite companies, and it's cool that they were able to resolve this without going head to head in court over it.