In addition to Bess's post. More competitions.

National Park Photo Competition – BIODIVER CITY
http://www.nparks.gov.sg/cms/index.php?option=com_chronocontact&Itemid=162

DIGITAL MUSIC COMPETITION
http://dmc2.musictec.edu.sg/

2nd National Earthquake Competition and Clean Water Challenge
http://www.sp.edu.sg/wps/portal/vp-spws/

Singapore2010 Blogs — In celebration of the Singapore 2010 Youth Olympic Games
http://singapore2010.sp.edu.sg/blogs/schedule/

Safety Starts With Me Competition 2010 http://www.ifsw.org/photocompetition

Singapore 2010 Logo Design Competition
http://www.singapore2010.sg/public/sg2010/en/en_multimedia/en_contest.html

Tourism Innovation Competition – Secondary School
http://www.tp.edu.sg/events/tourismcompetition/Registration.htm

‘Our World’ Photography Competition 2010
http://www.ncc.org.sg/ncc

Singapore Hamster Club – Singapore 2010 Competition
http://www.sghamsters.com/board/index.php?showtopic=4484