Hey there!
Do you just need medical qualification? I, too, got one of these and as soon as I got medically qualified recieved the official acceptance packet.
I believe it means most likely we will not be heading to USNA for class of 2013. And no not everyone recieves an offer to NAPS; some people recieve LOA's or appointments to USNA, some recieve appointments to NAPS, some recieve a Foundation Scholarship, and some are flat-out rejected (the much dreaded 'thin-envelope').
No, you definitely do not need a nomination to attend NAPS. All you have to do is complete the conditional requirements and you're good to go.
Yes, we will need another nomination to attend USNA in 2010. I believe all NAPSters apply to their MOC's; some do get nominations from them. NAPSters also qualify for the Secretary of the Navy nomination for active duty military.
Great job; be proud! I hope your planning on accepting the offer!