Web Snapper is an app and Safari plug-in that provides a fast and flexible way to capture screenshots of web pages. The Mac OS provides some very limited screen-capture capabilities with Grab, but Web Snapper provides many more options (especially in terms of format, and in its easy-to-use integration with Safari), and it can capture multi-page vector PDFs with actual text, links, and styling intact.
Web Snapper gives you a few different options for your interface, which will likely vary based on your workflow and browser preference. Using any browser, you can drag and drop URLs onto Web Snapper's main window, and from there you have a range of options open to you--letting you send web pages to disk, email, or your printer, as PDFs or in several other formats (BMP, GIF, JP2, JPG, PNG, and TIFF). In Safari, you can add a Web Snapper button to your toolbar, which lets you get pages to Web Snapper more quickly. Or, best of all, you can also print or auto-save directly from Safari, without even opening Web Snapper--which can be an extremely fast way to capture PDFs if you don't need to tinker with the settings for each individual capture.
While its easy enough for casual users (say, for example, for saving receipts), Web Snapper will be most useful for web designers and developers, with tons of thoughtful features such as the ability to use pagination, save multiple pages into one PDF, and even handle web trickiness such as Flash and DHTML. If your workflow requires you to capture a lot web pages as PDFs, Web Snapper's strong feature set, refined interface, and responsive support make it a good value.