What is the difference between nasal H1N1 vaccines and the injected H1N1 vaccines?

The only real difference is the medium that holds the virus in the vaccine, one is made for injection into muscles and the other is for using as a nasal mist. The current vaccination for H1N1/09 is available in both types of vaccines. The virus used in both vaccines is the same, except the nasal mist uses "live attenuated" viruses (they are still active whole viruses but have been treated to weaken them so they can not make an otherwise healthy person sick). The viruses in the vaccine for giving in a shot are totally inactive ("dead") or are just pieces of the virus particles instead of the whole viral organism, which also can not make you sick. See the related question below about which is better to use for your circumstances.