can i use a at&t go phone plan on a iphone unlocked or on a different unlocked phone from a different carrier?

Ok i wanna know if i can get a at&t go phone plan to work on a tmobile phone unlocked or a unlocked iphone or a different unlocked phone

If the iPhone is unlocked it will accept any GSM network.So you can choose any unlocked iPhone.Only locked iPhones face the problem of "Invalid sim" when a different network is used.Recently,I was a victim to it...but got a permanent remote unlock solution from unBBlock.com and removed the network restriction.