Here is a pick of a comet that will make a close enough pass by earth to be seen by the naked eye if away from city lights. It is blue green in appearance, it has a normal comet tail and also a tail facing the oppisite way. At any rate I think that this is very good candidate for the Hopi prophecy of the Blue Star marking the beginning of the ramp up to 2012.
I know the Hopi had already declared another blue comet that exploded and could be seen in the desert night sky as the blue star from the prophecy. The should I guess know better than me which one it is. However, I would still not rule this one out completely.
Pic Of Comet Lulin