PowerShell Get Exchange 2007 Database used space

Aaron on http://powershellcommunity.org asked “I need to get a nice simple list of DB sizes based on how big the mailboxes are, not how big the .edb file is. All of my DB’s are on 100gb disks. A particular EDB might be 90 gigs, but the database could have 40 gigs of whitespace in it. […]