Okay, Flock is basically a social web browser based on the Gecko rendering engine and the powerful XUL engine from Firefox. It integrates sites like del.icio.us and Flickr directly into your browser, built in support for blogging (via XMLRPC) and a while lot of other nifty things.
The beta was made publicly available today, you can get it here:
http://www.flock.com/
I'd recommend checking it out.
I took a little bit of a look at it and my review is here:
http://www.surfionline.com/archives/2005/10/21/flock/
Screenshots tagged as 'flock' can be found here on Flickr:
http://flickr.com/photos/tags/flock
Coverage on Technorati:
http://technorati.com/tag/flock
Take a look - it's quite an interesting browser.
