PG and dynamic statements in stored procedures/triggers?

Hi!

In other RDBMS I found a way to make dynamic statements.
I can use variables, or concat the SQL segments, and execute it all.

:tablename = call CreateTempTable;
insert into :tablename ....
drop table :tablename

or (FireBird like cursor handling):

sql = "select * from " || :tablename || " where..."
for select :sql ....
...

Can I do same thing in PGSQL too?

Thanks:
dd