usability: give feedback when a user clicks a tab

On the main contact view page (and I'm assuming anywhere else that we use the jQuery tabs) if a user clicks a tab, an AJAX request happens and the tab is then loaded. However this takes a second (or more depending on how far away you are from the server) and meanwhile the user is wondering what is going on, clicks it once or twice more, and then the tab shows up. We should use some CSS to set the cursor to the hourglass, or maybe go so far as to use a throbber.