web based ftp

I am trying to find a web based FTP for some clients who run a film company. I've tried using a php system called netftp, but my host will only allow 2MB transfer through php for security reasons they say. I used a java written web based ftp that worked fine for me, but the mac users claim it doesn't work.
I'd like to give them the option of using windows explorer, but they're all a terrible bunch of users who think that the syntax ftp://me@mydomain.com is toodamn complicated, and when i try to make a button just link to that type of an address, it won't work.
any suggestions?