AppleCare for iPhone will be available "...in July"
Your hardware coverage will be extended for up to 2 years
Customers will be provided with a loaner iPhone if theirs is out for repairs (after a $29US "rental fee")
They also list the specifics of the rental unit (you can transfer your data to it and an 8GB phone will get you an 8GB loaner) and exactly what type of things will void your warranty. The only thing missing is the cost of the program, though $60US has been suggested.