Enabling non-anonymous users in vsftpd

I've been trying to enable user access to vsftpd in SuSE 9.2. I've added "guest_enable=YES" to /etc/vsftpd.conf, but users still are denied access. There is also a string variable called "guest_username", but I have no idea what's supposed to go there. Anonymous ftp login works fine. Any ideas? tnx jk