Setting up a postgres and PostGIS server is not always easy, especially on an headless server, but I found the following instructions helpful, even though the instructions were designed to install Mapnik. I just followed the Ubuntu instructions, and it worked flawlessly.
http://wiki.openstreetmap.org/wiki/Mapnik/PostGIS
The PostGIS 2.0 shp2pgsql Command Line Cheatsheet was also helpful with importing shapefiles.
http://www.bostongis.com/pgsql2shp_shp2pgsql_quickguide_20.bqg