According to Weekly Shonen Champion, the second season of Shinryaku! Ika Musume was announced.

A collaboration of Ika Musume with a car racing team LMP Motorsport was also announced. "Ika Musume LMP Ferrari" will participate in Super GT 2011 games.

Source: Scan of Champion

Shinryaku! Ika Musume 2 on MAL

Update on May 24th
Title: Shinryaku!? Ika Musume

Staff
General Director: Mizushima Tsutomu
Director: Yamamoto Yasutaka ("Senjou no Valkyria: Gallian Chronicles")
Series Composition: Yokote Michiko
Animation Director & Character Design: Ishikawa Masakazu

Source: Scan of Shonen Champion
Production Studio: Diomedea