Mike Poulson posted this quick registry hack to move your attachments and emails from your device's own memory to a storage card.  A registry editor is included with some of the devices shipped out there; some not.  If you know of a good (free) one that works with SmartPhone / PPC please post a comment.

https://blogs.msdn.com/mpoulson/archive/2006/01/09/510839.aspx