cd ~/Library/Mail/Mailboxes/
Create a new Mailbox:
mkdir Local.mbox(or whatever name you like)
Change the permissions for the mailbox:
chmod 755 Local.mbox
Create the Info.plist (with vi):
vi Local.mbox/Info.plist
Go to the INSERT mode by hitting i, and paste the following XML statements (the !DOCTYPE line needs to be one line, not two -- shown as two here for width reasons. Replace the return with one space):
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN"
"http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>DisplayInThreadedMode</key>
<string>yes</string>
<key>SortOrder</key>
<string>received-date</string>
<key>SortedDescending</key>
<string>YES</string>
</dict>
</plist>
Exit vi by pressing the Escape key, then typing :wq. Now link to your mail in /var/mail:
sudo ln /var/mail/$USER Local/mbox
That's it...
[robg adds: I thought we'd run something like this before, but I can't find it anywhere ... so my apologies if this is a dupe!]

