The title doesn't even come out until July 15th, but you can preorder now if you want to secure the game for cheap. As for what Wordmaster is? Well, think Lingo or Jotto, only on the DS.
On a side note, you can also pick up Petz: Hamsterz 2 as Amazon's "Deal of the Day" for $11.99. Um, woot?
Source: Wordmaster for $13.99
Source: Petz: Hamsterz 2 for $11.99 (today only)