Posted 16 January 2012 - 14:57
Hopefully this reply isn't too late.
Home Sharing shares whatever DRM/Non-DRM content is tied to an Apple ID from one's iTunes library for up to five devices. So you can have one computer pushing content to any combination of 5 Home Sharing enabled devices.
You can use multiple Apple IDs, but you can only use one at a time. To stream the content from the computer to the Apple TV, you have to enable Home Sharing in iTunes, enter the Apple ID and password for the account you want to use, and then do the same on the Apple TV. Also, you have to have iTunes running on your computer while you're streaming, so if it pops back an error saying that it can't find anything, make sure it's running.
If you want to stream from a different account, just enable Home Sharing for that iTunes account and Apple ID, then change the ID and password you have saved at the Apple TV.
Hope this help.