LogonAssist lets you store all your username and password information in a single file, protected by a single master password. When you want to log on to a password protected site, you simply start LogonAssist, give it your master password, select the account you want to use, and press the logon button. Your default Internet browser opens and takes you to the site, where you can cut and paste the relevant information from LogonAssist. Any amount of information can be held: you are not limited just to Username and Password, and you can use different field descriptions for each account.
More info:
hxxp://www.berrick-computing.co.uk/LogonAssist/index.htm