Script Kiddies

How come some supposedly script kiddies what are still in their teens and still use windows manage to crack into huge international websites?

Is somebody that is actually capable using them as a proxy?

Or are some websites so insecure that can be cracked easily using known and ages cracking suits/methods?

Wtf is going on?

I have a related question. I'm an inexperienced desktop application developer who is try to transition to web development. I'm getting myself acquainted with LAMP (Perl) and the necessarily markup (HTML/CSS) and a bit of JS.

I just realized that I'm very ignorant regarding security measures. Is there some uptodate web archive out there that I can trust to inform me of the latest security holes (server/client side of any type) and how to combat them?

I don't want to put my future users at risk.