The other day we told you how to get Facebook chat in your browser's sidebar, but what about if you want to run it as a standalone desktop application? If you're a Mac user you're in luck with Gabtastik from Mesa Dynamics. It lets you run Facebook chat, and several popular Web chat services on your desktop without having to open your browser.
Besides Facebook, it supports the Google Talk, and Meebo, which means you can jack into all of the major chat networks such as Yahoo, MSN, and AIM. You can also tweak the opacity to blend into the background when you're not using it--a great feature for people with small desktop real estate who like to keep several windows open.
I gave it a brief spin earlier, and it essentially opens up a mini browser to get your credentials then resizes. You also can only use one iteration of each service at a time, which might quell the usefulness for folks who want to run two or more of the services at the same time.