Blueberryware

The email spam protection will convert the shortcode [ escapeemail email="email@address.com" ] to 

<script type="text/javascript">
eval(unescape('%64%6f%63%75%6d%65%6e%74%
2e%77%72%69%74%65%28%27%3c%61%20%68%
72%65%66%3d%22%6d%61%69%6c%74%6f%3a%
65%6d%61%69%6c%40%61%64%64%72%65%73
%73%2e%63%6f%6d%22%3e%65%6d%61%69%6c
%20%61%74%20%61%64%64%72%65%73%73%
20%64%6f%74%20%63%6f%6d%3c%2f%61%3e%27%29'))
</script>

which writes email at address dot com into your post.

Based on the email obfuscation found at http://twitter.com/help/contact

You can download this plugin here.

If you don’t want the plugin (or don’t have WordPress) you can generate the code for yourself: Email Spam Protection