Hi. Actually I’m a high school student and I’m practicing for improving my programming skills.
I’m looking for some Web sites for contesting in them.
For example:
Do you have more suggestions for me? I mean more Web sites for online-contesting.
Thanks a lot.
You are already aware of some of the best Programming Contest Portals. Some of the Other Programming portals are:
International ACM Programming Contest
There are many others also.But i think above list is more then sufficient. 
I’ll link some contests instead of judges: (I think I’m forgetting some)
IPSC http://ipsc.ksp.sk/
Annual competition. Very fun!
Challenge 24 http://ch24.org/
Annual competition. Also very fun
USACO http://www.usaco.org/
Not only it has a wonderful training site, it hosts competitions every now and then. It starts around november.
SPOJ has a contest page!
High school programming league 2012/2012 is running right now.
Codecup http://www.codecup.nl/
Annual competition. The objective is building a player for a game.
Google Code Jam
Facebook Hacker Cup
AI Challenge http://aichallenge.org/
I don’t know if this will be held again there has been three editions, I hope so!
There’s a list! http://clist.by/
This is thanks to ‘aropan’ of Topcoder and Codeforces