This and Rewrite are IMO the best L/Misa fics.
Marlee Cross' review
As you may have already guessed, this story is based on Legally Blonde. It does deviate what with the Kira case being what it is of course, so it's really only loosely based. The characterization of Misa is probably the best part as it shows that she really isn't as dumb as some people think she is.