Yesterday I published our first contribution to the atlassian community:
http://confluence.atlassian.com/display/CONFEXT/Obfuscate+email+addresses

Simple user macro to obfuscate email addresses on public pages using javascript,
somewhat more complex than the 'user at domain' approach - which is being parsed by
the email harvesters. Note that email can still be retrieved if the spamspider runs the javascript.

Put something like

{maillink:user=john|domain=acme.com|link=Need information} 

on your page.
The macro generates a javascript that generates

<a href=mailto:john@acme.com>Need Information</a>

when viewed with a browser. If parameters of the macro are missing (such as user, domain or link) the macro generates a usage statement.