Word's come out of a truly hideous iPhone Firmware 2.0.2 bug that allows any one who picks up your phone full access to your data... even if it's password protected.
Here's how it's done. Access is gained through the "Emergency Call" option on the password entry screen. Now hit the Home button twice. You're now at the favorites screen. Hit a blue arrow next to a contact's name. Want access to email? Make to email them, then email someone else. Want to use Safari? Go to a contact's web site, then just browse as normal. Easy. And totally stupid.
If you want to secure your iPhone before the obviously forthcoming point release fix, just assign your home button to something besides "Phone Favorites."
But jeez, Apple. Another fuck up? This will not go over well with your business users. You've spread yourself way too thin.