The Windows Mobile Team Blog has a glossary of mobile phone "locked" terms. If you've ever wondered what the difference between SIM Locked, Bootloader Locked, Application Locked, PIN Locked (or Device Locked), and SIM PIN Locked are,
(confused yet?), then this site may be of some assistance to you. So go fill your head with knowledge so you know (or can at least act like you know) what you're talking about at the next mobile phone party, conference, or whatever.