Facebook has just implemented a new system called Send. You can send any information to your selected friends, group(a whole group) and email list. You need to implement the FBML system on your website to success this. Just type the following code to do for PHP based server.

<script src=”http://connect.facebook.net/en_US/all.js#xfbml=1″></script><fb:send href=”<?php echo “http://”.$_SERVER[‘HTTP_HOST’].”/”.$_SERVER[‘REQUEST_URI’] ?>” font=””></fb:send>

In the above code, all are the same except the statement after href=””. I have give the PHP code so that the corresponding code will execute on you website and the corresponding link will be shared among your friends. You can paste same code to any wordpress website. You can just add a widget and then paste the above code. Note that your widget runs PHP codes.
For Pages:
You can just type: <fb:send href=”[YOUR URL HERE]” font=””></fb:send> on the Static FBML App.
In my opinion, this plugin is a worth for Spammers than normal people. It was better with share, but adding a mailing system would spam a whole lot of world as FB mails always goes to INBOX.
Implementation info here.
Enjoy.