Currently Being ModeratedNov 5, 2013 11:55 AM (in response to Goodredroad)
I am not aware of Google doing this.
An AIM Account can do but the are limits.
The Computer has to be set as if it is the United States (System Preferences > Language and Text > Region)
The phone involved does have to be on one of these Carriers
Obviously you have an AIM account to use in iChat or Messages.
You display the Buddy list if it is not doing so already.
You Add the person's phone number as if it were Buddy including a leading +1 for the United States
You then text/IM as normal.
Example of mousing over such a Buddy in Mavericks/Messages 8
The phone involved is a made up one (+1234567890) which the app spaces out and adds parentheses and dashes.
The Text is then sent from your AIM Screen Name and the AIM Forwarding deals with the link to these carries and the end phone.
iMac 2.5Ghz 5i 2011 (Mavericks 10.9)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad