My buddy called me up today.  Seems his '86 Jetta Turbo Diesel decided it was
too cold to start and left him stranded at home.
I went over this afternoon and here is what we did that got the engine going.
Put a lamp with a 100 watt light bulb under the hood.
Put an electric grille under the base
Within an hour of putting the grille under the motor (fit perfectly under
there), she had cranked and was running.
My friend had tried for a whole day to get it to crank before calling me for
help.
He also had neglected to plug in his block heater (which would have avoided
the whole problem in the first place).
So if you are having cold start problems, these methods work (just keep the
light bulb off of anything plastic or rubber) and might help you out of a jam.

Just FYI.

Thanks,
Ken Wilford
http://www.vanagain.com
John 3:16
Office (856)-765-1583
Shop (856)-327-0027
Fax   (856)-327-2242