The h1n1 bit is just a small component of the flu. They are molecules that cover the virsu surface.
The h stands for hemagglutinin and is the bit that helps it get bind on to a cell and allows it to get in, the n is neuraminidase, it helps it get out.
The number after the letter (ie 1) says which receptor on the human (or animal) cell that the h and n bonds on to. So you can have different h1s or n1s. It isnt a label that is specific to one particular flu virus.
The swine flu is a very different virus from the h1n1 seasonal flu. It has components from swine, avian and human flu bugs. Thats why the seasonal flu vaccine doesnt help. As long as it doesnt drift too far away from how it is now then any vaccine made using this swine strain should help protect against future strains of the swine flu. The more it changes though, the less help vaccines made now will be.
helpful article hopefully