See press release here
Wiki page for DoTA
If you don't already know, DoTA was an extremely popular Warcraft 3 mod. It's an RTS game that utilizes hero units as an integral part of combat. The point of the game is to destroy the opponents structures (known as ancients).
A while back, Valve hired one of the original devs for DoTA, so we can now see why. Valve has said that the game will be a straight remake in the source engine. However, Blizzard recently unveiled (after Valve) that there will be a DoTA mod for Starcraft 2. Since Valve is attempting to copyright the term Defense of the Ancients, it's created a bit of controversy. It also begs the question whether Valve will add new features to the game since the SC2 version will defiantly have improvements on the old game.
