Part 1: officially released

The Big Guns - on the album Rabbit Fur Coat.
Born Secular - on the album Rabbit Fur Coat.
The Charging Sky - on the album Rabbit Fur Coat.
Fireplace - b-side of You Are What You Love single. Not played live.
Handle With Care - on the album Rabbit Fur Coat. Traveling Wilburys cover.
Happy - on the album Rabbit Fur Coat.
Happy (Reprise) - on the album Rabbit Fur Coat.
It Wasn't Me - on the album Rabbit Fur Coat.
Melt Your Heart - on the album Rabbit Fur Coat.
Paradise - b-side of Rise Up With Fists!! single. Played live on Jenny's Spring 2006 tour.
Rabbit Fur Coat - on the album Rabbit Fur Coat.
Rise Up With Fists!! - on the album Rabbit Fur Coat.
Run, Devil, Run - on the album Rabbit Fur Coat.
You Are What You Love - on the album Rabbit Fur Coat.

Part 2: unreleased songs

Acid Tongue - New song debuted by Jenny live on the Fall 2006 tour. Jenny had mentioned in interviews that this song may end up on Rilo Kiley's next album, but that didn't happen.
Carpet Bagger - New song debuted by Jenny live Fall 2006. It's a duet with Johnathan Rice.
Cold Jordan - Cover song played on the Spring 2006 tour as the set-closing song. Also know as simply "Jordan", or with the difference split as "(Cold) Jordan", it's a traditional gospel song that Emmylou Harris and the Grateful Dead used to play. On it, Johnathan Rice handled most of the vocals, with Jenny harmonizing.
Dorothy's Song - Apparently an unreleased original song that was at one point in the running to be on Rabbit Fur Coat, but didn't make the cut. Jenny has performed it live at least once (8/23/04).
Fernando - New song debuted live at Spaceland in Silverlake, CA on June, 30, 2006. Played on the Fall 2006 tour.
Jack Killed Mom - New song played at most JL+WT shows in 2006. It's an uptempo number featuring a spoken word part by Johnathan Rice. Sometimes called "When Jack Killed Mom".
Little Boxes - Cover by Jenny and Johnathan Rice of the theme song to the TV show "Weeds", used on the show on October 23, 2006.
Met Him on a Sunday - Song by 50s girl group The Shirelles, later covered by Laura Nyro in the 70s. This later version is the one Jenny fell in love with when she was young. Sung at most of Jenny's shows.
Under the Black Light - New song played live once (12/08/06 Portland, OR). This song would later be recorded by Rilo Kiley and become the title track for their 4th album.
Untitled - New song played at most JL+WT shows in Spring 2006. Sometimes known as "(There Will Be) No Leaving Tonight" or something like that, though an official name hasn't been given to it yet.

Part 3: other songs Jenny sings on

Big Picture - Bright Eyes song with Jenny and Blake talking at the beginning
Be Still My Heart - The Postal Service song with Jenny on backing vocals
Behind the Frontlines - Johnathan Rice song with Jenny on backing vocals
Big Boat - M Ward song with Jenny on backing vocals
Bloody Murderer - Cursive song with Jenny on backing vocals
Brand New Colony - The Postal Service song with Jenny on backing vocals
Catch My Disease - Ben Lee song with Jenny on backing vocals
Clark Gable - The Postal Service song with Jenny on backing vocals
Do You Wanna Come Inside My House? {Jenny's Foxfire song} - short song sung by Jenny in a scene in that movie.
Greetings In Braille - The Elected song with Jenny on backing vocals
Inmates - The Good Life song with Jenny on backing vocals
Intentions - Whispertown2000 song with Jenny on backing vocals
Lean Back - Whispertown2000 song with Jenny on backing vocals
 Magic Man (live) - Heart cover. Jenny with Nada Surf on their tour with Rilo Kiley in August 2001. Not officially released. No known recordings.
Napoleon's Hat - Bright Eyes song with Jenny on backing vocals
 Nothing Better (live) - The Postal Service song with Jenny on additional vocals, live 2003. Not officially released, but there are recordings out there.
 Radio Campaign - M Ward song with Jenny on backing vocals
 Recycled Air - The Postal Service song with Jenny on backing vocals
Roll On - also know as "A Warm Bed Is Something", this is a song Jenny recorded with Jimmy Tamborello for Dntel. Jenny has performed an acoustic version of the song live at least once, 8/23/04.
 Sad Sad Song (live) - M Ward with Jenny on backing vocals, live July-August 2003. Not officially released, but there are recordings out there.
 Sierra - Cursive song with Jenny on backing vocals
 Sleeping In - The Postal Service song with Jenny on backing vocals
 Such Great Heights (live) - The Postal Service song with Jenny on backing vocals, live. Not officially released, but there are recordings out there.
Summer In The City - Vietnam song with Jenny on backing vocals
 The District Sleeps Alone Tonight - The Postal Service song with Jenny on backing vocals
 The Recluse - Cursive song with Jenny on backing vocals
 There's Never Enough Time - The Postal Service song with Jenny on backing vocals
 Through a Hole - Whispertown2000 song with Jenny on backing vocals
 We Will Become Silhouettes - The Postal Service song with Jenny on backing vocals
 We're All In This Together - Ben Lee song with Jenny on backing vocals
 What'll I Do - The Watson Twins song with Jenny on backing vocals
 You Again - James Figurine song with Jenny on backing vocals