I've created a basic workflow to create a bit.ly link, which is then copied to the clipboard.
I wanted to have some way to have a Notification Center popup to indicate the link was created successfully, but I haven't figured that part out yet.
You need to have an account with Bitly, and edit the Run Script section to copy your username and API key into place, where it says USERNAME_HERE and APIKEY_HERE. You can get your API key here, when logged into Bitly.
Download the workflow here.