Looks like you won't need to wait until September to use your plastic instruments to rock out to Kings of Leon's "Sex on Fire," included in Guitar Hero 5. Harmonix and MTV have announced that a Kings of Leon track pack -- along with music by Rancid, Rise Against, and Lush -- is coming to the Rock Band Music Store next week.

Kings of Leon pack ($5.49/440 MS Points for pack; $1.99/160 per song)
"Crawl"
"Molly Chambers"
"Sex on Fire"

Rancid pack ($5.49/440 MS Points for pack; $1.99/160 per song)
"Last One to Die
"Ruby Soho"
"Time Bomb"

Rise Against pack ($5.49/440 MS Points for pack; $1.99/160 per song)
"Prayer for the Refuge"
"Re-Education (Through Labor)"
"Savior"

Lush - "Sweetness & Light" ($1.99/160 MS Points)

Additional tracks available for Wii (July 21):

Big Dipper                                  “All Going Out Together” *
Big Dipper                                  “She’s Fetching” *
Big Dipper                                  “Younger Bums” *
Judas Priest                                “Dissident Aggressor (Live)”   
Judas Priest                                “Eat Me Alive (Live)”
Judas Priest                                “Prophecy (Live)”
The Dead Weather                       “Hang You From the Heavens”
The Dead Weather                       “No Hassle Night”
The Dead Weather                       “Treat Me Like Your Mother”
Jethro Tull                                  “Hymn 43”
Naked Brothers                           “Body I Occupy"*
Naked Brothers                           “I Don’t Want To Go To School” *
No Doubt                                   “Bathwater”
No Doubt                                   “Don’t Speak”
No Doubt                                   “Excuse Me Mr.”
No Doubt                                   “Ex-Girlfriend”
No Doubt                                   “Hella Good”
No Doubt                                   “Hey Baby”
No Doubt                                   “It’s My Life”
No Doubt                                   “Just a Girl”
No Doubt                                   “Running”    
No Doubt                                   “Simple Kind of Life”
No Doubt                                   “Spiderwebs”
No Doubt                                   “Sunday Morning”
No Doubt                                   “Underneath It All”
 
Price:           
$2.00 (200 Wii Points) per track
*Denotes $1.00 (100 Wii Points) per track

Tracks available for Rock Band Unplugged (July 23):

Grateful Dead                              “Casey Jones”        
Thin Lizzy                                  “The Boys Are Back In Town (Live)”
 
Price:           $1.99 per track on the PSP system