different samba problems


well, this should be an easy one for you guys out there, but it's got me stumped.
i've got my smb server running and everything, and it's great
now, i want to figure out how to set the password to access shares
as it stands now, i can access them with my OSX account info, but of course i wish to change this.
Also, if possible, I would like it so that users only have to know a password to connect to a share, regardless of their username.
That said, can anyone give me a hand or a hint?
I'm still getting used to the smb.conf options, but you could probably find plenty of help if you sniff around some samba-related or linux-related discussion boards.