Yup. I assume we're talking Outlook password *NOT* eMail password. I'm going to treat you like a neophobic person--sorry if you aern't. Open Outlook, go your inbox--now click where it says "Inbox" this should open a pane that shows all your folders. Click the little push pin. Right click where it says "Personal Fodlers." Click "Properties..." go to the advanced tab and hit "Change Password"
All of this is from memory of Outlook 2000 (Not express) I haven't touched Outlook (Lie, I still use it when I'm on my dads computer) since I installed Linux.