Making A Hl Modification

Zerogreat

<div class="IPBDescription">why? why not!</div> When i would like to try to make some HL mod, what do i need? I think there are some official tools for this but dont remember the name. Also is somewhere some kind of "tutorials" for making HL mods or such?

BOZO

Go here: <a href='http://collective.valve-erc.com/' target='_blank'>http://collective.valve-erc.com/</a>

Zerogreat

Thanks