Google has enabled MMS within Google Voice on more than 100 networks in North America, including AT&T, Sprint, and T-Mobile in the U.S.
Google Voice was previously limited to sending and receiving only SMS messages. For the moment, Verizon has not enabled MMS via Google Voice, and Google didn’t say whether or not it intends to.
Some of Google Voice’s features have recently been ported to Google’s Hangouts app/service, such as the ability to make voice calls.