Recursive queries

Hi all,
I have a question that probably is more apropriate for pgsql-dummies but
since I use postgres and don't know what list would be more
apropriate... here goes:

I have some data that I want to be able to search by geographic location.
The geographic locations are stored in a table with a reference to their
parent location (i.e. Germany has a reference to Europe whis is in the
same table)

I am wondering what the best aproach is when I want to perform a search
by location and need to include all child locations.
For example I want to return all results applying to the European Union
which means it should include all childcountries, provinces, cities, etc
in the search.

Any suggestions, or pointers to sources of info?

Thanks,
Rob Hoopman