Unlike Game 1, tonight will not be so simple, because the NHL and NBC have moved from regular broadcast network to the cable station of NBCSN (Dish 159, Direct TV 1220, check your local listings). By now you probably already know the channel, since most of the Pittsburgh Penguins playoff games this spring have been on NBCSN.
There's also an online stream here from NBC, but it requires a cable subscription.
For our international friends, the game is on CBC if you're in Canada, and if you're overseas you're probably hardcore enough to know what you have to do to be watching.
There's also the radio, with Mike Lange and Phil Bourque on the call, on 105.9 The X in Pittsburgh, but you can also get that stream online for free, and through the Pens app on your phone as a good way to listen, as a commenter pointed out last time.
Radio: 105.9 WXDX (listen online)
Stream: NBC Live Extra