Hey there's 2 interesting and working programs to jailbreak your Ipod Touch or Iphone easily .. but there's also the manul mod.
I suggest you to use the one I'll tell.
First you can use
First program is Iliberty+ if you search on google you should find lots of thread talking about it but no download link so here is it:
RapidShare: Easy Filehosting
You need to have your Ipod Touch/ Iphone plugged in your computer.
Open Iliberty+
For Ipod touch: Steps:
1. Be sure that Jailbreak is checked.
2. Click on Go for it !
3. Wait until it's complet and it should work
Fore Iphone: Steps:
1. Check the one you want but be sure to always have jailbreak checked.
2. Click on Go for it !
3. wait until it's complet and it should work
This was for Iliberty+ really easy
The other way is by using Ziphone
Downloads ZiPhone Download Server - IPhone and IPod Touch Software For Ipod Touch: Steps:
1. Open ZiPhoneGUI.exe
2. Click on Jailbreak
3. Wait until it's complet and it should be correct
For IPhone: Steps:
1. Open ZiPhoneGUI.exe
2. Click on Do it all ( but it can cause some problem to your Iphone So do it at your own risk )
3. Wait until it's complet.
The utility of jaibreaking an ipod touch or Iphone: For the Ipod Touch:
Jailbreaking your Ipod touch allow you to download third party programs. Somes third party program are emulator to play games with the touch screen. Others are to host web sites with apache, somes are to boost the sound quality or your music. Also with an jailbreaked Ipod touch you can connect to it as a ftp, so you can change your background and icons. You can instal windows xp and Linux on your ipod when it's jailbreaked only. Also if you doesn't have a phone but you or your parent have a wireless internet connection, with VOIP-SIP you can make your Ipod touch a phone by using internet connection. You can do much more than this with an Ipod Touch jailbreaked.
For The Iphone:
Jailbreaking an Iphone give you the same thing as a Ipod touch Jailbreaked but if you doesn't want to pay with at&t for a cell network you can active it with programs like ziphone that is always update to work. Activing your Iphone will allow you to connect it via another cell network.
This is a guide made by myself

Good luck