Isn't it not a bad thing to jailbreak it nowadays?
Yeah....Jailbreaking has been easier then ever. You just have to go to jailbreakme.com and click on something and then after like 5-10 minutes, it's done. If you updated the firm wear to OS 4.1, then you can't jailbreak till there is an update from the hackers.
But still....do it when you can and you can always reset your phone to factory settings which won't void your warranty if you have it. And who wouldn't want to download free apps! I have probably 50 paid apps now.