CSI:New York's Feb. 6 episode will include a Second Life component. Viewers will be able to experience additional content by going in-world via a special, newbie-friendly app from Electric Sheep.

MIT Technology Review has more here.
CSI: New York site here

Thanks to Rob Webber for that lead.

Meanwhile, over at CW,

[There's the network's] new drama "Gossip Girl," about prep-school students living in Manhattan's Upper East Side. To promote the show, CW's half-owner, Time Warner's Warner Bros., worked with Millions of Us to build a virtual Upper East Side neighborhood, where users can shop on Madison Avenue or see the school that characters from the show attend. The world, which just recently opened, uses the same underlying technology as Second Life, but visitors enter through the "Gossip Girl" Web site.

-Wall Street Journal

More info here