There is a skit on SNL that Will Farrell and one other lady do.  They
are a musical group at a school dance.  Will is playing the keyboard
and the lady is singing.  They talk about not being the originally
scheduled band to play. I know that one song starts out with "Chaka
Khan, Chaka Khan". Where can i find this skit??

I believe you're remembering Will Ferrell and Ana Gasteyer as the
inept musicians Bobbi and Marty Culp. This was a recurrent skit; the
"Chaka Khan" episode at the prom was on a show hosted by John Goodman
on May 10, 1997.

"The Culps are last minute replacements at Woodrow Wilson high
school's senior prom. The original band, the Scooby-Don'ts, are having
van problems and it is the Culps to the rescue. I'm not going to
transcribe the whole sketch, because it is impossible to accurately
portray in print, but some of the songs have water themes since the
prom theme is '20,000 Leagues Under the Prom.' The songs they sing in
this medley are:

* I Feel for You (Chaka Khan)
* One of Us (Joan Osborne)
* Where It's At (Beck)
(at this point someone in the audience gives the Culps the finger)
* Come Sail Away (Styx)
Special Note: Will seems to love Styx, in 1996 and 1997 he made
reference to them quite a bit
* Rock Lobster (B-52's)
* Rock the Casbah (The Clash)"

http://members.aol.com/MLanza1974/ferrell/wf10.htm

I have been unable to find a place where you can view the skit, but I
hope this information will help another Researcher.