Answer straight from Samsung.....
I was wondering the same thing so I emailed Samsung Australia, this is the reply:
Thank you for contacting Samsung Customer Care.
The N8000 is a 3G variant of the Galaxy Note Tab, you are able to make phone calls and browse the internet using a network provider of your choice. Please be aware that there are two major different models with the Galaxy Note Tab, there is the GT-N8000 which works on the 900 band, this means that Optus and Vodafone will work and network providers under them, and there is the GT-N8000T which works on the 850 band, this means that Telstra and the network providers under them will work.
The N8010 is a WiFi only tablet. This tablet is unable to make phone calls unlike its 3G variant.
The N8013 is an overseas model of the WiFi variant and has not been released in Australia.
I hope this has been some help to you.
If you have any further enquiries, please do not hesitate to contact Samsung Customer Care on 1300 362 603.
Thank you for contacting Samsung.
Kind regards,
Kieren
Samsung Customer Care