I would recommend an every two-week email newsletter than addresses things like: new users, EMR news such as CCHIT, etc., what suggestions have been made that are good, what suggestions may be implemented in the future, what may not be implemented and WHY (such as code restrictions).
The main thing would be to address future updates such as Version 5. I think talking about it every two weeks is better than going three months and then finding out why the target date has been pushed back.
I think communication is the key between corporate and the users.
i completely agree, they will send a email announcement/newsletter when the new version is done, they have occasionally to let us know something new is on the horizon. Since they are behind their original schedule ("Summer 2009") it would be useful to have an idea of where they stand as well as what's new in the field. Some of this occurs naturally on the users board, but most of the time it is not official. Perhaps they could have a section of the board where they make announcements, then do not have to worry about changed emails or such.