Bypass, Skip Activation On iOS 5 [How To] :
2) Now launch iTunes and update your iPod Touch 4G using iTunes. To do this, connect it to your computer, click on the Check for Update button with the Option (Mac) or Shift (PC) key pressed. Select the iOS 5 IPSW file from the place you downloaded it to.
3) On the setup screen, push the home button 3 times until VoiceOver activates.
4) Hold the time on the status bar.
5) Drag down the screen with 3 fingers.
6) Tap twice on the Y!
7) Push the Home button. Optionally, you can also Disable VoiceOver.
If you don’t want to bypass the activation process but activate it without a developer account or UDID registered, follow this tutorial.