I don't mind setting everything up by hand, but this can be error prone and slow. Webmin is a neat program with a web based interface that makes it quick and easy to set up mounts and shares, among other things. These are the the directions for Ubuntu Server Lucid.
Lets just cut to the chase....
sudo aptitude -y install perl libnet-ssleay-perl openssl libauthen-pam-perl libpam-runtime libio-pty-perl libmd5-perl apt-show-versions libapt-pkg-perl
(it'll give you an error about libmd5-perl, don't worry about it)
sudo dpkg -i libmd5-perl_2.03-1_all.deb
sudo dpkg -i webmin_1.510-2_all.deb
Now you should be able to point a browser over to http://ipaddress and begin configuring.