"Jailbreaking" is another word hacking. Therefore you void your warranty but you get cydia, a jailbreaking software. Jailbreaking does have it advantages and Disadvantages. But if you want to send it to apple to repair it you have to restore it to factory settings to get back your warranty.
jailbreaking the ipod touch is legal. But if you use the tool that gives you all apps free it is illegal.
It is impossible to get an installer on an iPod Touch without jailbreaking.
Yes; not jailbreaking it. If you mean a way to do the same thing as jailbreaking without actually doing so, there is no current way to do so.
It is up to you. No matter what you have on your ipod will become messed up when Jailbreaking...
You cannot get all apps for free without jailbreaking an iPod Touch. It is not possible.
Yes, jailbreaking does void the warranty.
no
you cant
No.
As of today (November 24th, 2010), jailbreaking an iPod Touch is not illegal. Is it 100% safe? No.
No, not without jailbreaking your iPod 2g.
no, but i woudnt try it