W3C is holding a Workshop to discuss HTML in email. The event will be held in Paris on May 24. There's a call for paper with a deadline set to April 21. Daniel Glazman summarizes what they are looking for :
In particular - but this is not limited to that - we would like to hear from Mail User Agent and HTML authoring tool vendors, users with security concerns related to HTML email, users with interoperability issues, online retailers sending their ads and newsletters in HTML, companies doing marketing on the mobile market and sending HTML messages to mobile devices, and so on.