MAKE SURE YOU BACK-UP ALL YOUR STUFF BEFORE JAILBREAKING!
1. Update your device to iOS 4.2.1 (To check go to Settings-General-About-Version) This is the latest firmware for the iPod touch 2G/iPhone 3G, but if your device has newer firmware go to a different link at the "How to Jailbreak" page. This tutorial is meant for iPhone 3G and iPod touch 2G. If your newer device (3G, 4G) is already at iOS 4.2.1 then you can use this tutorial and forget about updating.
2. Download Greenpoison here for windows and here for mac
3. Unzip/extract the file to the desktop.
4. The folder will open and take you to a screen which as two things- Greenpoison and Read Me. You can read the Read Me if you want. Open Greenposion by double-clicking on it.
(remember to connect your device and TURN IT OFF)
5. Follow the directions Greenpoison asks you to do. (Its pretty much self-explanatory.) The first thing it tells you to do is to put your device in DFU mode. Just follow the steps. You can not start to jailbreak until your device is in DFU Mode. Try multiple times to get perfect timing. You know that it is in DFU mode when it say "Jailbreak"
6. Once it's in DFU mode. Greenpoison is automacially jailbreaking your device. A lot of letters will appear. Just let it do it's thing. It will reboot will the greenpoison skull image and the Apple boot logo.
7. When it is done, find the app "Loader" and tap on it. Tap on Cydia and tap "Download Cydia" This will install cydia. Cydia is the "store" that you download jailbroken apps.
8. The device will restart itself. Once it's done restarting, you've installed Cydia. There is an icon called "Cydia"
9. Congrats you've jailbroke your device on iOS 4.2.1! If you lost any data in this process, you can sync your iPod/iPhone with iTunes to get it back.
