With the new 2.0 Exchange support you can get locked into having a passcode and auto-lock setting on your phone. Even manually changing the plist you will then be asked to set a passcode again at least once a day. Instead of updating your plist everyday, just simply click on KillExchangeLock and your plist will be set to not require a passcode and never auto-lock. There aren't any preferences at the moment, but it can be a godsend for people who don't like the restrictuions that the current Exchange support provides.
