Amsterdam Netherlands 80,000 (Indymedia),
Athens Greece 200.000 (Indymedia)
Aukland New Zealand 10,000 (Indymedia),
Bagdad Irak 20,000 (CNN), hundreds of thousands (Al Yazira)
Bakaa Refugee Camp Jordania 500 (Palestine Chronicle),
Bangkok Thailand 3,000 (ANSA) ,
Barcelona Spain 1 million (Indymedia Barcelona)
Beirut Lebanon: 60.000 (indymedia)
Bellingen Australia 2,500 (Indymedia),
Berlin Germany 500,000 (Indymedia),
Bern Switzerland 30,000 (Swissinfo),
Brussels Belgium: 11.000 (indymedia)
Cairo Egypt 2,000 (Palestine Chronicle), tens of thousands (local media)
Canberra Australia 16,000 (Reuters),
Cape Town South Africa 5,000 (Indymedia),
Copenhagen Denmark 20,000 (Politiken) 50.000 (organisers)
Damascus Syria: tens of thousands (various media)
Durban South Africa 3,000 (Indymedia),
Gaza Palestina 15,000 (AFP),
Helsinki Finnland: 12.000 (indymedia)
Hobart Australien 10,000 (ABC),
Jakarta Indonesien 200 (Jakarta Post),
Johannesburg South Africa 10,000 (Indymedia),
Kolkata Indien 10,000 (AFP),
Kuala Lumpur Malaysia 2,000 (Malaysiakini),
Lismore Australia 5000 (Indymedia),
London UK 500,000 (CNN), 750,000 (police) 2 million (organisers & indymedia)
Manila Filippinerna 6,000 (Rai),
Melbourne Australia 200,000 (Indymedia),
Monza Italy 5,000 (Indymedia),
New York USA: 100.000 (organisers)
Newcastle Australia 20,000 (Indymedia),
Oslo Norway 60,000 (Indymedia),
Paris France: 250.000 (organisers)
Pattani Airport Thailand 10,000 (Reuters),
Perth Australia 10,000 (ABC),
Rome Italy 1 million (CNN), 3 million (organisers)
Sarajevo Bosnien 500 (Rai),
Seoul South Korea 10,000 (AP).
Sevilla Spain 250,000 (Indymedia)
Stockholm Sweden: 30.000 (Indymedia)
Stuttgart Germany: 50.000 (Indymedia)
Srinagar Kashmir India 2,000 (Reuters),
Tokyo Japan 25,000, (ANSA),
Turin Italy 1,500 (Indymedia),
Vienna: 15.000 - 30.000 (Indymedia)
Wellington New Zealand 5,000 (Reuters)

compilation from local sources and these 2 articles:

 http://euskalherria.indymedia.org/eu/2003/02/4295.shtml
 http://sweden.indymedia.org/front.php3?article_id=37356&group=webcast