Turning column into row - Mailing list pgsql-sql

Hello,

I'm afraid this is a blody beginners question but I have no idea how
to perform a search sanely in the list archive.

I have a Table of certain items
  create table item (      IdItem      int,      Item        varchar(64),      ...  );

a lookuptable which defines some properties
  create table property (      IdProperty  int,      Property    varchar(64)  );

and a table which defines the different properties which are possible for
a certain item:
  create table tlkp_item_property (      IdItem     int,      IdProperty int  );

So I can easily select all the properties of a certain item in a table
where the columns contain the properties.  But I want to have an output
of the kind
   Item 1: Property 1, Property 2, Property 3, ...   Item 2: <Properties of Item 2>      ...

So I have to turn the different properties according to one item into
one field insead of one column.

How to do this sanely?

Kind regards
         Andreas.