Who do I talk to about . . ?

Running a Contest:

Contact Russ at russ at defcon dot org to inquire about running a new contest or if you currently organize one and have questions.
(Note: For info on the individual contests themselves, check this thread on the DEFCON Forums.)

Being a Vendor:

Read the Vendor FAQ first, then contact Chris at chris at defcon dot org to apply.

Getting a Skybox:

Apply for Skybox space with Grifter at grifter at defcon dot org.

Being a Speaker:

Answer the Call for Papers!

Being a DJ:

There is an Call for Talent currently open which you may find here, the contact person is Zziks at blackandwhitedjs at gmail dot com.

Getting in touch with The Dark Tangent:

DT's contact info and public key can be found here.

Website and Program Submissions:

Submit updates for the website or material for the printed program to Neil at neil at defcon dot org. Anything to be published in the printed program is due June 30, 2008.