How to set up "Find My iPod Touch" 3G without MobileMe

Hi, I have an iPod touch 3G and want to set up "Find My iPod Touch" on it, as described here:

http://www.apple.com/ipodtouch/find-my-ipodtouch-setup/

I'm running OS 4.3.4 (8K2) and have iTunes 10.4.1. I have an AppleID but not a MobileMe account. I understand that since iCloud is replacing MobileMe, they are not accepting any more subscriptions (not that I'm anxious to pay $99/year for what will now be a free service). I'm not sure I want to create a new account anyway, because all the apps I own are linked to my current Apple ID which is not an email address.

I have a program called "Hidden" for my Macbook which works via wi-fi. If I lose the Macbook, I log into the Hidden website and it triggers the Macbook to broadcast its location via wi-fi (assuming it's within range of a signal). So I would assume that since an iPod touch has wi-fi capabilities, it could do something similar even though it's not directly linked to the internet like an iPhone.

Does anybody know how I can get this going?

My son has an iPad 2 that is wi-fi only and I would like to set up the same for him.

Thanks for any help you can give!