Can a iPhone break by jailbreaking it?

Answer 1

Yes, and it happens very often.

Jailbreaking your iPod is very risky, because it can corrupt the software, but more importantly, ruin the hardware. If you are not sure what you are doing, then do not jailbreak your iPod.

Answer 2

While it is in fact possible to "Brick" your iPhone while jailbreaking it (if not done properly) you can always just do a hard restore in iTunes and restore from backup :)

Answer 3

It voids your warranty meaing if you have insurance thats voided too.....I wouldnt recommend it unless you have no type of warranty or insurance on your phone