Well, that will be the reason to for me not to buy one... I do not own an iPhone and do not want to buy one, just to use with my Tablet PC. As stated on mosspuppet.com this is the work of a genius (Steve Jobs): "he’s essentially offering a $1,000 computer as an accessory to a phone."
I think however that this is a mistake Apple is making. On the other side: I may be the only person with an unlimited mobile data subscription that is not used very often. I would be very happy to put my SIM in the Apple Tablet.
Let's wait and see what the real specs of the Apple Tablet are.
Regarding the picture I included: credits and original picture via mosspuppet.com.
The upside to all of it: it might safe me spending $1000!