i doubt they will stop selling Intel based MBP's. this will probably be for a lower end laptop for the $500 laptop market.
as it is now a $500 laptop about $200 goes to Intel/MS for the hardware and OS. add in the screen and other hardware. the margins on them are razor thin. it take 8 cheap HP laptops to equal the profit of one MBP.
If apple can make a $500 laptop that does the basic tasks for most people it's all over for Intel/MS in the lower end laptop market. Internet, email, basic games, basic apps. there will still be $2000 MBP's for photochop and xcode and other big tasks but for most people a $500 apple laptop will be a killer deal
and there will tens of thousands of apps at launch with the mac app store and iOS app store