Billboard Bits serves up the best bite-sized nuggets of music news and gossip.

Britney Spears Finished with Three New Songs

Following her appearance on last week's episode of "Glee," Britney Spears is reportedly hard at work on her next album and has finished three new songs. "She loves 'em," a source to the singer says of the new tracks. ( TMZ)

Kurt Cobain Letter to MTV Up for Auction

An unsent letter from Nirvana's Kurt Cobain to MTV is up for auction at Julien's Live, with the current bid at $2,500. Cobain refers to "Empty TV" as "the entity of all corporate gods" in the note, which is handwritten on lined notebook paper. (Julien's Live via The Daily Swarm)

Train's "Hey, Soul Sister" Ad Use Bashed on Tumblr

A new Tumblr blog titled "Stop Advertising From Pulling a Train" has debuted with the intent of chastising TV advertisers for their rampant use of Train's hit "Hey, Soul Sister." "Know an ad that uses this song? Submit it… so we can keep track of everyone who apparently needs some new taste in music," the blog reads. Since debuting on Monday, the blog has received nearly 30 different submissions. (Stop Advertising From Pulling a Train)

Jordin Sparks Debuts Fragrance Line

"American Idol" star Jordin Sparks has partnered with fashion retailer Dots for her debut fragrance, "Because of You." The scent, which includes "clementine, white imperial currant and orange blossom," will be exclusively features at the retail chain through Nov. 5.

YYY's Karen O Releases 'Jackass 3D' Song

Yeah Yeah Yeahs singer Karen O has released "You're Gonna Be Dumb, You Gotta Be Tough," a country-tinged Roger Allan Wade cover set to appear on the soundtrack to "Jackass 3D." The album, set for digital release on Oct. 12, will also feature contributions by Weezer, Twisted Sister and CKY. (Some Kind of Awesome)

Alter Bridge Announces Third Album

Alter Bridge will release third album "AB III" on Alter Bridge Recordings on Nov. 9. The rock group, which includes former members of Creed, will soon issue "Isolation" as the lead single to rock radio. 

(Reporting by Jason Lipshutz)