Comic Browser is an application that allows you to easily read online web comics such as User Friendly and Penny Arcade.
Here are some of its features:
Click here to get a list of supported comics.
You can download comic browser from sourceforge
Unpack the archive and then run the following as root: "python setup.py install", or you can also run "python comicbrowser" (as your normal user) if you just want to run it without installation