Not in XP home without third-party software. Could you keep the file on a USB memory stick? That works for me and I can carry it with me if I need to use someone else's PC. I also keep all my ftp and email account details in that file.
I, too, have a sieve-like head when it comes to passwords.
As well as the USB stick, I also make use of the password manager in Firefox as much as possible. This is compatible with the login forms on nearly all sites and you only need to remember one password and use it once per session on a 'when-required' basis.