Sharing files between Ubuntu and Windows

At first I was using Xubuntu, Ubuntu with Xfec. Following this post I was able to visit shared folder of one computer in the same network, after I modified the WORKGROUP of Xubuntu. But I couldn't get access to my Win2003 Server, because it is password protected.. I had to switch to Ubuntu with Gnome. Nautilus, the file explorer, is more friendly than Thunar. Select Go->Network, I am able to visit my Win2003 Server using username and password.

Now it's time to share files in Ubuntu. After modifying the /etc/samba/smb.conf, I could see the shared folder from Nautilus, but not from Windows box. When I tried to access this folder from Windows box, I was prompted to input username and password, and my username/password is always rejected. The reason is that the system is asking for username/password of SAMBA, not u/p of Ubuntu. The solutions is to create a samba password:

sudo smbpasswd -a ben

After doing so, I can visit Ubuntu shared folder from Windows box.