Google is on a roll with new released and updated features lately. They’ve just announced that Gmail calling now supports multiple calls, call waiting, and hold.

You’ll now have the ability to put someone on hold during a call, accept another incoming call, and switch between the two calls; just like a land line that has call waiting enabled. The only limitation with this new capability is that you’re only allowed two outgoing calls to physical phones at the same time.

As Mashable pointed out last year, U.S. and Canadian calls placed through Gmail’s phone and video system will be free through 2011. Best of all, these new multi-line features work with Gmail’s phone, voice and video calls.

Official GMail Blog