Writing competitions for children

[usernametaken]

Is there a central website or listings site where I can find writing competitions for children. DD has just won a competition and is very keen to do more! I'm googling but not a lot is coming up.
Many thanks.

There definitely won't be a central site, but there are a couple of 2012 competitions listed here and it might be worth skimming through the web-sites of some of the larger children's publishers (e.g. Usborne).