Back in May, I tested and reviewed various (static) screen capturing programs and options for OS X. Although I did not have a chance to actually address the issue of full web page captures in that article, I was, and continue to be frustrated by the lack of a good, Leopard-friendly program that can capture an entire web site, and not just the portion that appears on the screen. Stitching together screenshots in Photoshop is time consuming and unfortunately, Paparazzi's Leopard support is kludgy (.43 works with Leopard, but .5 won't even open). I demoed Web Snapper, but it is a Safari plugin (or InputManager for the semantically correct), which is not always ideal.
From the Realmac website, it looks like LittleSnapper is really designed to take the best aspects of a program like Skitch, the ability to capture portions of the screen and annotate and share with other people, with the ability to work with web browsers and also organize screenshot libraries. They even show off a DOM-highlighter, so you can instantly capture a specific element of a site, much like Safari's WebClip and CSSEdit's Inspector.
We'll let you know more about LittleSnapper as the details eke out. You can sign-up for updates at Realmac's website. LittleSnapper will be a Leopard-only application.