ChanScan is the premiere browser specifically made for viewing imageboards.
4chan420chan2chanPonychanOperatorChanfChan
Other Features Include:
> Built-in Animated GIF viewer> Slick one-touch interface for easy browsing.> Posting Support (Captcha Compatible)> Built-in Image Gallery> Built-in Image Viewer> Favorites Lists> Ability to download all images from a thread.> Multi-language character support (Roman, Japanese, Russian)> Image Cache for quick browsing.
The list of boards is easily expanded as the boards are dynamically defined in an XML file. The developers will make their best effort to add any requests to the default list but openly welcome users to make their own lists.