Thanks to .ark for the information
Invision Power Services, the company behind products such as Invision Power Board (which our forums run on) and Invision Gallery, have announced a new webmail product called Vectura.
Invision Power Vectura will allow you to offer a powerful yet intuitive webmail system to your users. Vectura features a cutting-edge interface that will make checking your webmail an enjoyable experience wherever you are.
The guiding intent for Vectura is to blend the usability of traditional desktop e-mail applications with the flexibility of existing webmail systems.
Invision Power Vectura is written in PHP and uses MySQL database storage.