http://drupal.org/node/11517. I have done this using some command line magic:

find . -name README -exec cp '{}' '{}.txt' \; -exec cvs remove -f '{}' \; -exec cvs add '{}.txt' \;

I will update all occurences of 'README' to 'README.txt' in the conrtib CVS,
soon. I'll also rename LICENSE, CHANGELOG etc. files as soon as I get around
to it.

Add optional 'write to author' links for nodes/comments (modified patch by jik)
other minor code updates/cleanup

- Theme system updates: theme() function return their data now.

Patch by Craig Courtney (thanks!)

- updated to latest cvs, should work in Drupal 4.2
- added folders, you can move messages in folders, empty folders
- mail once per day if you have unread messages (user option)
- message pruning (move old messages to another table)
- list of contacts: it's built automatically looking at users you write to
- theme()ized
- if you are updating run you just need to run privatemsg.sql

- Updated the private message module to CVS.  Patch by John Cappiello.