Creating a project plan is fine but then getting the task percentage
completed updated is tedious. I'm suggesting a cut-down mode (it may even
be the existing planner application but with a different menu/ui skin)
which allows team members to update completed statuses for tasks and to
APPEND task and resource notes (note append not write).

The project manager can then go away and when they come back they are able
to  see what the updated completion status of tasks and commit those.

Imagine a really simple GUI which has the tasks (by resource or similar)
and the tumbler as well as a Append Note... button and thats all. 

Further enhancements would be to actually make the main project file
read-only and have the clients write to a separate "delta" file e.g.,

myproject.mrplanner  group:read
\updates\myproject.<resource>.mrplannerstatus  group:read/write

The update could also be on file or emailed thus allowing for real-time or 
email based collaboration or updates. We may also introduce a simple data
check of some kind (e.g. MD5 or SHA with a shared secret).

Well thats the thought at this time.