Nomad and Necro i have tried it myself following each and everyone thing using blackrain step by step but when ever i restart my touch it asks me again for itune to plug in the device and i have to restore it again.. :S
what you are experiencing is due to your ipods
updated bootrom and well you cannot do anything about it. it's known as a
tethered jailbreak and you have to do what you are doing every time you reset your device!
the paragraph below talks about 3gs but is also applicable to the new 3rd gen ipod touch.
"Note: For those of you who are planning on jailbreaking your new iPhone 3GS with the updated bootrom, you should be aware that BlackRa1n supports only a tethered jailbreak. This simply means if you have to reset your phone or your battery runs out on you, you will need to connect your device to your computer and run BlackRa1n to be able to boot your iPhone."
Source:
http://www.theiphoneblog.com/2009/11/22/jailbreak-unlock-iphone-3g3gs-blacksn0w-mac-edition/
search google for tethered jailbreak and you'll get to know more.