There is a special spriter plugin in C2 already. Never tried it, but there you maybe don´t even need to export PNG´s,
Another Animation-Option would be Flash, which let´s you export as a sprite sheet or Png-sequence very easily.
I have a little problem i have full master collection of adobe cs3 with flash but it is not installing there is a problem in files . So i want to make character using alternative body parts sprites and then use bone or something like that feature to set movements ex . Spriter (Brash monkey) It can use timeline for animation movements like using in after effects . The software is also able to export sprites in png in frames (Images) to import in c2 . But i told you i have a problem with the spriter so if you have a similar software to make sprite characters tell me .Or if this plugin is able to do these things then can you tell in brief , How it works .