These are songs that Busted have co-written.

McFly

Radio:ACTIVE album
Everybody Knows
Do Ya
Motion In The Ocean album
We Are The Young
Lonely
Wonderland album
Memory Lane
Room On The Third Floor album
Five Colours In Her Hair
Obviously
That Girl
She Left Me
Down By The Lake
Unsaid Things
Surfer Babe
Broccoli
Other
The Guy That Turned Her Down [from one of their singles, don't know which]
No Worries [from I'll Be OK single]

Other

V feat. McFly - Chills In The Evening [featured on one of V's singles]
Melanie C - Immune [featured on her latest album]
Pat Monahan - Great Escape [featured on his solo album]
Nicholas Jonas - Appreciate [not sure where this is from]
William Tell - Yesterday Is Calling [iTunes bonus track on William Tell's solo album]

If any of the lyrics are wrong, please email me with the corrections!