I'm setting up a website or three, and I'm getting tired of FTPing files this way and that. I'd like the simplest possible solution for keeping a local directory tree in sync with the directory tree at my FTP site. What's the best (free) tool for this job?

Windows or Linux are both fine for me, I just want the easiest possible way to "set it and forget it" and have my local file changes automatically kept in sync with what's on my FTP. Can't use rsync or install any additional daemons, so it needs to use FTP. I do have the lufs and ftpfs installed in my Linux machine, so I could do funky things using FTP automounts, but I'd prefer something a little less kludgy and more reliable.

The one caveat is that it'd be nice if it supported multiple accounts, since I have multiple FTP logins for different web sites.

So, any suggestions?