A google search will yield plenty o results...however, in my opinion, most proxy servers are shady. Free ones could be worse.
You don't. There's just a package to run, and then you have to start an app whenever you want to use Tor.
It really depends. Why do you want to use a proxy? Security? Anonymity?
In other words, circumventing a forum IP ban?
You realize that you will eventually be found out and banned again, right? Why stay somewhere you are clearly not welcome?