Budding Timbalands and Missy Elliotts have the chance to pitch their beats to Slick Rick, who's prowling online for guest producers to work on his next album.

In a promotion on the StreetLabs Web site (www.streetlabs.com), producers can listen to sample beats from old Slick Rick tunes, including "Mona Lisa" and "Children's Story," and then upload their own. The rapper is looking for beats with a "cartoonish vibe that he can tell a story to," according to the site.

The promotion will run until the end of August, according to Def Jam Records. No release date has been set for the album, which will be Slick Rick's first since 1999's The Art of Storytelling.