9/19/2012 - Changed recipe, costs less. 9/20/2012 - Changed recipe, costs just the right amount. 9/20/2012 - Now able to teleport infinite times.
Basically, this mod adds a sword to the game. The Ender Sword. It has the stats of a diamond sword, but gives the unique characteristic of being able to teleport as many times as you like!. It's fairly expensive, a stick, two Ender Pearls, and 8 diamonds. This video goes into more detail about the mod and includes installation instructions.