Multi-person SMS startup 3jam has launched a new tie-in with Virgin Mobile USA: 3jam SMS 2.0.

The new service provides an improved level of text messaging by allowing friends and family to connect by multi-party text-message conversations. The 3jam application is free and requires no subscription, however standard text messaging rates apply.

The launch marks the first time a U.S. mobile operator has launched a multi-party text messaging product. Virgin Mobile USA currently has 4.8 million subscribers.

For 3jam the deal is a competitive advantage in a crowded vertical; having a tie up with a telco is a definite positive that will see many, many more people exposed to their product. See our previous coverage of the space here.

3jam took $4 million in funding from Norwest Venture Partners and New Enterprise Associates in July 2007.