I have an
.ai project open in Illustrator, that I need to export to multiple PNGs with different resolutions.
Is there a way to write a script or automate these exports in some way?
You can create an Action to do this. These instructions are for CS5/Win:
You can now open any another file and run the action by clicking the play button. The limitation is the PNGs will save with the same names in the same folder as when you recorded the macro. If you want more control or want to run the action on multiple files you can look at the options in Batch Mode (click the tiny menu button at the top right of the panel, choose Batch...).