The swine flu actually starts off like a normal influenza attacking the respiratory system. However, if the virus is left untreated long enough, it begins attacking the nervous system relentlessly until the host dies. It's also a very young virus so it does still have the potential to mutate into something with a higher kill and infection rate. The chances of it doing something that severe is very low.
However, if a patient with rabies were to contract the swine flu, there is a short chance the viruses may interbreed creating a new strand and mutating into something strange. In this case, the virus would attack the nervous system and respiratory system simultaneously, killing its victim quick. The symptoms would probably similar to the common flu at first, escalating into uncontrolled fits of rage, muscle spasms, and continuing flu symptoms. The swine flu, a zombie does not make.
