I need a way of controlling my friends computer from outside the network. I am at school and he is at a different school so VNC won't work b/c theres no way I can just connect to his school ip address. Is there another way to do it? Remote Desktop isn't an option, how bout remote assistance?

Likely there isn't much you can do in this case. I'm sure both schools not only have remote access blocked, they'll be looking for attempts to connect remotely too.

PCanywhere type of installed applications may work. Many companies/shcools allow it for their techs.
Other options such as gotomypc sort of options may work.
Remote desktop web connection or remote assistance may work.
Messengers may work too, some offer whiteboard or even remote desktop features.
There are stunnel options that may work also. You tunnel your application such as vnc to allow port and protocols to be encased in other packets.
I have read here about hamachi but have never used it.

As above your issue will be the ports issue. You may have to make some type of vpn to the computer. Much more difficult.

I used to like barracudaserver for file access but it isn't free anymore.

I read it wrong and answer it wrong too. So get off my case you peanut.

Use LogMeIn. It's secure and easy to setup.

It uses HTTP port 80 so the connection won't be blocked at the corporate firewall.

"Computer security." — Oxymoron