We have chosen Cocos2d framework to develop our game (and to learn objective-c !) because:

• A lot of games use it (so it is mature)
• The community is very active
• A lot of tutorials and books are available. 
• No need to learn openGL.
• It’s free and open source

We used Illustrator, Photoshop and Flash for creating and animating graphics.

TexturePacker was used to create sprite sheets in pvr.ccz format.

We start developing on Iphone then we discover Ipad and decided to make a universal binary (SD graphics on Iphone 3G / 3GS, HD graphics for Iphone 4 / Ipad). The game is greater on Ipad!