Now you don't even need to install Kindle's Mac or PC app to read some free pages out of ebooks. Amazon just released "Kindle for the Web", which allows free browser sampling and site embedding of any Kindle preview pages.
Readers should get a kick out of thumbing through what's usually the first 10-20 pages of any book they're thinking about picking up, even if they switch back to actual paper. Readers also get links to share those chapter previews by email, Facebook or Twitter, which can come in pretty handy for sharing the stuff you really dig. Bloggers and site administrators can also benefit by embedding those books in any page they have access to, like so:
Kindle for the Web doesn't require Flash or seemingly any other plugin, and it's free to use.