The important thing to remember is that Desktop and Server are the same underlying OS, with different packages & configuration
In Windows that isn't true
(tx to @jay-bazuzi)
This is a step-to-step answer.
Install samba
sudo apt-get install samba samba-common
Install some dependencies for Configuration tools
sudo apt-get install python-glade2
Installa samba configuration tool
sudo apt-get install system-config-samba
Make a new user Jones
adduser Jones
Make a Linux password for user jones
passwd pirat9
Open samba configuration tool.
Add the folder you want to share and setup the permissions
Create a samba user
sudo smbpasswd -a jones
New SMB password
retype New SMB Password
You can chose any directory you want to share by right click on the folder directory and open the share options
Now at this point if your ubuntu server has ip: 192.168.1.10
you can access to your folder with a Linux Machine typing on Nautilus address bar:
smb://192.168.1.10/pirat9
or on a windows machine with:
\\192.168.1.10\pirat9
Thanks Linuxman for screen and refs:
http://www.unixmen.com/howto-install-and-configure-samba-share-in-ubuntu/