This plugin by Bannerweb GmbH automatically encodes every e-mail address on posts, pages and sidebar widgets to prevent spam. Simply decodes any previously encoded e-mail address by just clicking the mail link.
The simple mail address encoder finds every linked e-mail address in posts, pages and sidebar widgets and encodes these to prevent the mail address owner from being added into a spam list by spam crawlers searching the web for unsecured mail addresses.
This plugin does not have any graphical user interface – just activate it in your WordPress backend and let it do its job.
Tested on WordPress 3.0!
Plugin homepage: http://www.bannerweb.ch/unsere-leistungen/wordpress-dev/simple-mail-address-encoder/