First of all, you will have to make sure that the users on your Windows machine also has an account on the linux machine. (Linux will then create a home account. This gives the user rights to the home(username) directory).
Next, you will have to (as root)assign this user an smbpasword.
ex. I have the user joe logged in to my windows machine. I create the user on my Linux machine(with linuxconf or useradd joe etc.)Then , still as root user, add the command smbpasswd -a joe.
You will be prompted to add new password. Use the same password as your Windows user.
ex. links:~# smbpasswd -a joe (joe is a linuxuser)
New SMB password:(here add smb password)
Retype new SMB password:(repeat password)
Password changed for user joe(verification prompt.
Also, check to see that shares are browseable. You can do this easily with swat.(I think I answered another question from you about swat).
By the way, the smbpasswd can be configured using swat. Main point is to makesure that the user exist in linux and that this user has rights to the folder you are trying to share.
Hope this helps.
As far as the comment above to look in the Man pages or docs, I think you did well coming here to techrepublic. I have many tips here as well.
