Creating tables from within functions

Is it possible to issue a CREATE TABLE statement from inside of a PostgreSQL
function? If not, then how about from within a PL/pgSQL function? I have
tried a lot of different permutations but can't seem to get it to compile
and/or run cleanly. For example, consider:

CREATE FUNCTION _testcreate () RETURNS text AS '
BEGIN
CREATE TABLE switch_table2 (switch_id varchar(32),
selection_name varchar(100));
end;
' language 'plpgsql';

What is wrong with this? What type should be returned? Or perhaps it is
simply not possible to create a table from within a function?

Please give me the reply soon as possible
Thanks!