I believe it goes something like this:

ALL:You know us as Team Rocket
And we fight for what is wrong
We're tired of out motto so we thought we'd try a song
JESSIE: Jesse!
JAMES: James!
BOTH: The speed of light! Prepare to fight!
MEOWTH: Meowth! That's riiiiiiight!
JAMES: I am the handsome one
JESSIE: I'm the gorgeous one!
BOTH: Looking good is lots of fun! We get some
things wrong but we keep rolling along!
ALL: We want to capture Pikachu! We hope to do it
soon! And when we do we'll be the new stars of
this...cartoon!