If you need help with PostGIS there are several ways.
Free ways to get help
To really learn PostGIS and a lot about GIS in general buy the book PostGIS in Action by the same authors as the tutorial above.
There is a webpage for the book with description of the book and discussions http://www.postgis.us
If you need professional help with PostGIS
or situations where PostGIS might be a part of the solution
take a look at the list of companies offering help.