[Zope] Python regular expression help

[ this might be more of a Python question, but it's got a lot to do with the web and is to be used in Zope ] I want to replace all occurences of email address's and URLs in a textstring, to <a href="mailto:%s">%s</a> and <a href="%s">%s</a>. Must admit that I am not an regex expert, and I wasn't able to find a "precompiled" regex for neither email nor URL. Or is there anything available from the zope/python stack?