Why give your film "to the lab"?
Download Open DCP
http://code.google.com/p/opendcp/
and make the film yourself. The film would not be key-protected, but do you care?
The problem - afaik - is, that there still is no reliable player to check if everything went well. As a digital projectionist, here is my advice: Find a cinema near your place, talk to the projectionist and spend coffee and cake, then give him the USB stick with your film and check it.
What kind of codec do you need to export? An RGB Tiff sequence. Be aware, that the DCP server needs a preset for your film size to play it properly. Most should have 1080 x 1920 (HD 16:9, though the standard cinema distribution format is 1108 x 2048, Widescreen 17:9).
The sound needs to be exported as 24-bit PCM 48 kHz, nothing else.
As frame rate, use 24 fps.
