(The feed is from mainstream media zoougla.gr)
Some quick translations:
Many people now in syntagma square
very few banners and more people are continiously gathering here
Large student attendance

slogans:

"Batsi gurunia dolofoni"
cops pigs murderers

"mesa sta kefalia sas exete skata ti na katalavete apo lefteria"
within your heads u have shit, what can u know about freedom"

athens indymedia coverage on this protest:
 http://athens.indymedia.org/front.php3?lang=el&article_id=943624