Basically what 13thmonkey already said, create a TrueCrypt volume and put your password file inside it. Then when you need a password just mount the volume, open your password file to get the password, then unmount the TrueCrypt volume when finished.
I'd go a step further and get a cloud backup solution for your TrueCrypt volume, so if your hard drive ever craps out you don't lose your passwords.
Here is a cloud backup solution that is free with a 2GB limit. If you need more than 2GB you need to get a paid account... http://mozy.com/home/free/