Hate the new Bitly? Me too. Fortunately the old Bitly Sidebar feature still works well.
To install: Create a new bookmark that points to this Java Script code:
Drag this into your bookmarks pane.
Once created, you can click on that bookmark from any page and Bitly’s tool bar will pop-up in the right rail. Copy, paste, presto.
Note: You may need to edit the bookmark and replace each ’ mark with new ones. Tumblr’s font confuses some browsers.Source: myurow.com