in /etc/samba.smb.conf, you want a section like this:
Code:
[myshare]
comment = Shared folder
path = /usr/somewhere/shared
valid users = you afriend
public = no
writable = yes
printable = no
create mask = 0765
if you don't want to mess about with smbusers, then set it to share-level security earlier in the file. If you want user-level security, you will have to add the users with smbpasswd. You're best off reading the manpage for that as how you use it varies depending on your setup.
there's a lot of help for you in the /etc/samba/smb.conf have a read of it and set anything you will need by hand.