Adam Lambert, Christina Aguilera, More Host New Year's Eve Parties

If you still haven't made plans for the countdown to 2010, here's a handy guide to the hottest parties with the hottest stars.

Looking for a good party this New Year's Eve? Well, there's no shortage of celebrities on hand to help you ring in 2010. Everyone from [artist id="3061469"]Lady Gaga[/artist] to [artist id="3188063"]Adam Lambert[/artist] to [artist id="976"]Mariah Carey[/artist] to [artist id="509026"]Christina Aguilera[/artist] will be hosting parties in cities like New York, Los Angeles and Miami. If you're still unsure of where you want to start your countdown, MTV News has put together a list of the hottest spots with the hottest stars.

In Los Angeles, Adam Lambert is the headlining act at the Gridlock New Year's Eve concert. Basketball star Allen Iverson has hooked up with Claudia Jordan and Mekhi Phifer for a Harlem Nights party at Siren Studios. And if you're looking for a little old-school hip-hop, Grandmaster Flash will be the man at the Roosevelt Hotel come New Year's Eve.

Christina Aguilera will be hosting a party at Las Vegas hot spot Tao, but a slew of other celebrities are scheduled to host parties up and down the Vegas strip. Nicole Richie and hubby Joel Madden will be at Lavo. And in addition to performing on Dick Clark's "New Year's Rockin' Eve," the Black Eyed Peas will appear at LAX Nightclub at the Luxor hotel. Fall Out Boy's Pete Wentz will join DJ Skeet Skeet at Jet nightclub.

Las Vegas will also be home to parties featuring Robin Thicke, who will perform at the Bank; and 50 Cent, performing at Pure nightclub. Former "Girl Next Door" Holly Madison will be joined by Jermaine Dupri for a bash at Privé.

The parties will be just as hot on the East Coast, with Cobra Starship's Alex Suarez and Ryland Blackinton and celebrity DJ Josh Madden rocking the night away at the Hotel on Rivington and then late night at the Eldridge, both in New York City. Meanwhile, after she plays Madison Square Garden, Mariah Carey will meet up with hubby Nick Cannon to host's M2 Ultra Lounge New Year's Eve 2010.

In Miami, Lady Gaga will play the hottest ticket in town at the Fontainebleau. "The Hills" star Brody Jenner will be counting down the last few seconds of the decade at's Gansevoort Miami Beach Hotel Rooftop New Year's Eve 2010 bash. Lady Gaga's former tourmate, Kid Cudi, will also be in Miami for a party at W Hotel Miami Beach, where he'll be joined by John Legend. And Wale, who also knows a thing or two about working with Gaga, will be at the Shore Club.

Don't miss MTV News' "Top 9 of '09" — which counts down the year's biggest stories, from Michael Jackson to Eminem and everything in between — airing New Year's Eve at 11 p.m. on MTV.