Here is a unique idea:  Cup Holder Car Mount for your Blackberry or Treo!  This looks great and your device is right at your fingertips for changing songs.

The cradle fits very tightly around the Blackberry and has a quick release button for when you want to move it inside.

Take a look at the pictures.  I'm sure you will agree that this is a heck of a lot better than putting it on your seat!  The popular Cup Holder Pedestal is about 5" tall.  It features an adjustable flywheel base that expands to fit varying cup holder opening except for those that are so large that the 7-Eleven Big Gulp falls over

Fits many Blackberry models including:

Blackberry: 6230, 7100G, 7100T, 7130C, 7130E, 7200. 7230, 7250, 7270, 7280, 7290, 7510, 7520, 8700C, 8700R, 8703E, 8705G, 8800, 8820, 8830

Bold:  9650, 9700

Curve: 3G, 8300, 8310, 8320, 8330, 8500, 8520, 8530, 8900, 9300, 9330, 9350, 9360, 6370, Touch 9830

Pearl 3G

Torch: 9850, 9860

Tour: 9800, 9630, 9810