iStrip is described as 'An application to view and archive comic strips available online - Download comic strip images and cache them for offline viewing - Support for over 600 strips built in - Keyboard navigation provides quick access to strips and dates - Save bookmarks for your favorite' and is an app in the News & Books category. There are five alternatives to iStrip for Windows, Linux and Mac. The best alternative is Buoh, which is both free and Open Source. Other great apps like iStrip are Woofy (Free, Open Source), yawr (Free, Open Source), Comica (Free) and ACMEreader (Free Personal).
Woofy is a pretty neat webcomic downloader, designed for simplicity and ease of use. Its purpose is to help you download and maintain an archive of your favorite online comics, while not getting too much in your way.
YAWR is a webcomic reader that connects to a webcomic of your choice (dynamically extensible via regex-based plugins) and displays or updates strips. The current version is based on SDL and written in the D programming language.
This comic viewer / comic reader lets you read your daily comics with ease. -ACMEreader stores comic strips in an archive. -ACMEreader keeps track of new and read comic strips. -New strips are shown in a different color.