Last year's issue of the Simpsons' Treehouse of Horror issue featured Nina Matsumoto's parody of Death Note, along with comics by Glenn Fabry and Gilbert Hernandez.

This year's issue is coming out on 9/23/09, and was guest-edited by Sammy Harkham. It's insane and packed full of PictureBox/Buenaventura comics people (including folks in Electric Ant #2: Jon Vermilyea & Ted May). Check out this cover by Dan Zettwoch, and panel from Jon Vermilyea's comic:

Full contributor list
Tim Hensley
Matthew Thurber
Jon Vermilyea
John Kerschbaum
Will Sweeney
Jeffrey Brown
Sammy Harkham
Kevin Huizenga
Jordan Crane
Ted May
Ben Jones
C.F.

What the hell is up with having no female cartoonists though? That seems kinda bullshit to me.