iPhone4 and development together with iPhone3GS iPad do?

iPhone3GS together to develop and iPhone4 and iPad
What image do I need to call?

iPhone4 iPhone3GS and the
“pDirector-> enableRetinaDisplay (true);” is when you call.

Do you create a separate project for iPad?

It depends on your game UI. But for most situation, I prefer to create a branch for ipad/android tablet version, separated from phone version.