Not so knowledgeable in automotive but my brother has a 2004 Classic 2.2L and we're planning to do a tune up and i don't seem to see any spark plugs in his engine, this is a first for me. But is there really no spark plugs on this type of vehicle or are they hidden somewhere?

The spark plugs are under the black rectangular cover on top of the cam cover. They are recessed way down in the cylinder head, common for this type of engine.
http://media.gm.com/us/powertrain/en/product_services/2008/Photo%20Library/Ecotec/L61/08%202.2L%20I4%20L61%20MAL%20LoR.jpg