Can I flash my AT&T iPhone 4 to Cricket Wireless?

I've tried researching this, but I keep getting conflicting answers. I've called Cricket customer service and they gave me addresses to full-service, corporate stores that do it; however, when I arrived the sales rep had no clue what he was talking about and kept contradicting himself. I've also looked on the internet, but again I get conflicting answers. Please help!

Added (1). @Zachary - How do I unlock it?

Sorry only CDMA phones (sprint, verizon,) can be flashed to cricket. GSM phones (at&t, tmobile) can be used with each other only if they are first unlocked. Hope this helps!