How do I change default programmes?

Hi all,
I find that a programme called VLC will play all or most of my video clips downloaded from Youtube or wherever but my Mac Mini insists that another video playing software programme is the default application for showing videos.
How can I make it so VLC is the Daddy?
Cheers,
Steve

Find a quicktime file and right click (control click).
Select get info and where is says 'open with' change that to VLC and then click change all.

Here's how it goes!

-Ctrl+click on the file that you'd like to open
-Click "Get Info"
-Underneath the "Open with:" section, you will see the default application
-Change the default application to whatever you'd like
-If you'd like ALL files of that specific type (.mkv, for example) to open with the program you've selected, click the "Change All..." option.

Hopefully this does the trick, and if not come back an' let us all know!

Find a quicktime file and right click (control click).
Select get info and where is says 'open with' change that to VLC and then click change all.

Click to expand...

You, sir, have used a good picture to go along with the steps.

Thanks guys,
All sorted now.
Steve