It's kind of a football shaped thing above the PCM connector when looking at it from the engine bay. Pop the plastic thing off and you'll find the hole underneath that you can run the wire through. Drill a hole through the plastic football shaped thing and run your wire through there.

 

Exactly what Chris described is what you should find. Mine is an Automatic, but there shouldn't be a difference. But then again I can't remeber ever seeing underneath the dash of manual either. Hope this works.