Is there a way to have my iphone ATT text messages automatically forwarded to Apple Messages on my Mac? When I'm using my Mac I don't always have my iphone handy so I would like to use my Mac to receive and send messages is this case.
That would be something you'd need to discuss with AT&T. Verizon, for example, offers a service called VZ Messages that lets you access your SMS messages from a web portal. Very handy. AT&T may offer something similar.
You'll have other options when iOS 8/Yosemite is released.