Can I put the sim card from my AT&T lg escape into an AT&T iphone 3gs?

I need a phone before i get an upgrade, and an iphone 3gs is the only phone I can really afford right now, but I don't want to buy it unless I know I can transfer all of my things onto this new phone.

No because the Lg Escape use micro sim and iPhone 3gs use the bigger mini sim. You can use a micro to mini sim adapter if you want to use your sim with a iPhone 3gs.