It clips in nice and tight. I bet you could use a cell phone belt clip, too.

Accessories for the Marware system (a soft case for the iPod), including the "car holder," are available at this site

What I do is untether the gascap, then everytime I refuel, I pick up the fuel nozzle, and place the gascap on the lower arm of the nozzle stand.

After pumping fuel, you'll never forget about the gas cap because you have to remove it from the fuel nozzle stand to return the fuel nozzle to its original position.

Off topic
 

Does the board itself host these pictures, or did you guys upload them to a viewable site and link it from your post?

I'm trying to post my pics with the IMG tag...

Click on attach file, below the text box, to post a picture.