Just found this while searching for discount/promo codes for Hertz membership:
http://www.gadling.com/2010/05/12/fr...miles-members/
https://link.hertz.com/link/goldcorp...orpType=ftgold
enter
Delta Skymiles as the program name, and
5765 as the promotion code
It worked for me. Unfortunately, having booked my car through hotwire for this weekend (and got Hertz), I still have to stop by the counter in Denver. Oh well.
Hope this helps some folks, and sorry if this has already been posted elsewhere (or if it belongs in a Hertz forum instead of the DL forum)