According to Weekly Shounen Magazine, Mashima Hiro's manga "Fairy Tail" was announced to get a TV anime adaptation. It will be aired from this autumn. The production studios are A-1 Pictures and Satelight.

Source: Scan of WSM

Note: The prevailed rumor that Mashima Hiro was an assistant of Oda Eiichiro is false. Mashima Hiro has never worked as an assistant of other mangaka.

Updated
Cast
Lucy: Hirano Aya
Natsu: Kakihara Tetsuya
Erza: Ohara Sayaka
Gray: Nakamura Yuuichi
Happy: Kugimiya Rie
Siegrain: Namikawa Daisuke

Sources:
Scan of WSM
Scan2