'Hacking'

Okay, inb4 Newfag, Read SICP, etc

I'll try not to sound like a 13 year old, when I say I'm interested in learning how to 'hack'. Not guess peoples passwords, etc.
Accessing someones computer via their IP address and being able to access files and suchlike.

Programming in what language makes this possible?

Also, any software around that can simply do this shit for me?

Oh yeah, I'm hacking you so hard right now, baby.