Xel: You’re wrong on several counts. First of all, you can do all sorts of things once you have an IP, assuming it’s the correct one (not a spoof) and you know what you’re doing. Secondly, ‘cracker’ isn’t equivalent to script kiddie. There -is- such a thing as a malignant hacker.
In more detail:
I’m definitely not l337 h4x0r, but I did work as a systems administrator, and part of my admin training was under the wing of someone who was, well, l337.
Basically, someone of my level really wouldn’t be able to do much on AIM (IRC is another matter), -unless- I could convince the person to open a direct connection with me (ie, message them and ask if they want to trade movies or warez or something). Once they do that, I can run a tracer (MS-DOS comes with one built-in, as I recall, for ping checking purposes; it’s called “tracert”) and get their IP address, which is essentially where they are on the internet.
That only works if they’re not spoofing, but anyway… that’s more technicalties. 
Once I’ve got their IP, I can basically send them packets without their being able to stop it (unless they’re behind something like a firewall, in which case it would take someone MUCH l337er than I to get through). Packets are little snippets of information/commands; with the proper packets sent in the proper sequence, I can do all sorts of nasty things, including any or all of the following; taking control of his computer (in other words, my input peripherals - keyboard, mouse, whatever - control what happens on his screen), shutting his computer down, downloading his files, deleting his files, messaging as him on AIM, kicking him off the internet every time he logs on, etc. I’m not good enough to code any of this stuff on my own, but I think most people who’ve studied hacking long enough would be able to do this stuff without much problem; the admin I trained under certainly did.
The fortunate part about all this is that most people who the media calls ‘hackers’ are just ignorant little kids who download ‘scripts’ (prepackaged hacking, so to speak) and don’t understand the material themselves, so they can’t tweak it or do anything too nasty unless they’re given the proper scripts.
Even worse, someone (again, I don’t know how to do this myself, but I’ve seen it done) they could just copy your registry files, decode them, get your keys (program reg keys, like for Windows and games and stuff) and use them themselves. If you’ve got passwords saved on Internet Explorer and such, they can grab those too.
That’s basically the gist of it, I guess. A lot of those internet viruses you hear about work the same way; once you’ve opened the files, they run themselves and do the stuff I mentioned above (about registry files) and then ‘report’ the results back to whoever programmed the virus. They’re basically just automated little packets of hacking.
If you’re worried about this stuff, there’s all sorts of protection programs you can get; Norton Antivirus will stop email viruses (at least the ones it knows of, and Norton is really good about updating), but as far as I know won’t stop system hacking. Stuff like ZoneAlarm will tell you if someone’s attacking you, and I think BlackIce will warn you of attacks and block them on it’s own.
I did learn a few of the basic things, but I’m far too poor at math and coding puts me to sleep, so I didn’t really get anywhere. Also, I hate using Linux. -_-;;;
That’s about all I can think of… if anyone else has any questions I’ll try to answer them, but keep in mind I don’t even remotely consider myself a hacker or anything
