What browser are you using?
If it's firefox you can go to the "tools" page and go to "options" and then into "security". There you will find some password functions that could be what you are looking for.
I think with IE you can right-click on your username and password after you enter them to log on and it will again offer to save them on the computer for you. I haven't used IE for a long time so I'm not sure how accurate that info might be.