Firefox: There are a few ways to send content from your browser to your Kindle (using Instapaper, for example, or the Send to Kindle Chrome extension). If you're a Firefox user, Amazon now has a more direct way for you to push web content to your device.
Once you install the Firefox browser extension, you can click on the Send to Kindle icon in your toolbar to quickly send the page you're on to your Kindle library. Other options are to send just selected text or to preview the page before sending.
In your Amazon Kindle settings, you can specify if you want to send using Wi-Fi or via Amazon's Whispernet service. In addition to the option of archiving docs in your Kindle Library, you can also choose which devices you want the documents delivered to.
It's great that this extension is finally available for Firefox. Amazon says a Safari version is coming soon.
Send to Kindle [Amazon]