Mac OS X 10.6: Adding a password to your keychain
You can add passwords for servers, email accounts, and other password-protected resources to your keychain. The next time you access the server or check your mail you won’t have to type your password.
To add a password to your keychain:
Open Keychain Access, located in the Utilites folder in the Applications folder.
Select a Keychain from the list.
Choose File > New Password Item.
Fill in the information for Keychain Item Name, Account Name, and Password.
You can select Show Typing to reveal the characters you typed to make sure they are correct.
To add a password for an application, look for a checkbox in the login dialog or other feature (such as a menu item or preference) that adds your password to a keychain. If you can’t find a way to add a password to your keychain, the application may not support keychains.