Need your help to solve my problem. I have 3 clients and 1 server = linux.
My mission is to setup a media file server where we store all media files on linux server. All 3 clients to have read access only.

Here is my smb.conf.
----------------------------
# Global parameters
[global]
workgroup = MDKGROUP
server string = Samba Server %v
encrypt passwords = Yes
map to guest = Bad User
log file = /var/log/samba/log.%m
max log size = 50
socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192
printcap name = cups
dns proxy = No
printer admin = @adm
hosts allow = 192.168.2.0/255.255.255.0
printing = cups

[media]
comment = music videos etc
security = share
path = /winshare/Media
username = guest
write list = admin
read only = No
guest only = Yes
guest ok = Yes
---------------------
Winxp can see the shares in Network Neighbourhood but each time I try to access it, it asks for user name and password. I have created a user=guest passwd=music for the smb and system still no sucess.

What I need is to access the share without user and passwd and read only.

Is your XP machine part of the same workgroup as the linux machine, if XP is in a different workgroup it will ask for a password. You could also moving the security = share from the share to the [Global] settings

Winxp machine have different workgroup name I will follow your instructions. Will get back.