Since awe.sm is a closed beta now, I've modified the sociable plugin to use bit.ly if selected in the Sociable settings menu on the dashboard. Anyone interested, contact me for details. For now, I've put a tar of it up on my website if you want to down load it and try it out. It's called "mysociable" so as not to conflict or overwrite the standard one. Just make sure to deactivate the old one before activating the one I hacked up.
Here's the code:
To see the diff, look here: