Override OnLinkClicked() and check the passed link info for the 'mail:' prefix. And if its there, don't call the OnLinkClicked() method of the base class, to prevent wxWidgets from loading this link as a HTML ressource.
Now, you have reduced your problem to: how do I call the standard Email client? I have no idea... Have fun, Noel -- http://mail.python.org/mailman/listinfo/python-list