The Daily Prophet took the first-ever Newsround Award, voted for by more than 1,000 people.
But it also picked up a second award for the best individual category.
The site was set up by 17-year-old American Heather Lawver and is like an online newspaper. Heather is editor and also looks after a global team of volunteers.
Fact File
C&W Childnet Award Winners
Individual - The Daily Prophet (US)
Not For Profit - Great Ormond Street Hospital (UK)
Schools - Willoughby School (Canada)
New to the Net - Young Biznet (Egypt/US)
Newsround Viewers - The Daily Prophet (US)
Heather saw how the Potter books got loads of kids into reading, and that gave her the idea to build a site that would interest people in creative writing too.
Now more than 100 children - all writing under Potter-style names - regularly post to the site with stories and articles all based around Harry's world.
Vuppet power!
Three other awards were handed out at the event at the Science Museum in London by a familiar face - Newsround's Lizo!
The vuppet helped Lizo present the awards!
He was helped out by Carol Vorderman and an amazing computer generated floating head called a vuppet - or Bill for short.
Twelve websites were nominated across different categories. And they were from all over the world too, including Australia, Sierra Leone, Egypt, Canada and Italy.
The C&W Childnet Awards have been running for six years. They aim to recognise the different ways that children work with the internet.
Hear story
I was guest editor on Newsround's website
