Now we're all calmer...*biffs* Oy! You! Yes you, stop talking up the back!
As I was saying, now we're all calmer, perhaps we can try to shed some light on why Snape went and did a baaaaad ting (think tweety pie here), and killed Headmaster Albus Dumbledore of doom.
The evidence for my thinking that Snape is innocent are as follows.
Un
Snape makes an unbreakable vow with Narcissa Malfoy yes? The terms are that Snape must kill Dumbledore on pain of death. Narcissa was of course, trying to protect her son, as any half decent mother would. Why does Snape accept? Because he has a heart *gizasp* and there are probably other factors which I haven't got around to working out yet.
Dau
Dumbledore's hand. It's black and looks like a prune that's been in the back of the fridge for a very long time. Not very nice. This I believe, was the result of him destroying the horcrux in the ring. Now Voldemort, as stupid as he looks, is in fact very intelligent. He isn't going to let someone destroy a part of his soul and get away with it. No sir. Upon destroying the horcrux, Dumbledore was hit with a slow killing curse. Hence the black hand.
Tri
Snape and Dumbledore's argument. I think it was Hagrid who overheard Snape and Dumbledore arguing behind Hagrid's hut. Don't quote me on this but I think Snape's words were "I don't want to do this anymore!" I bet you're all thinking that Snape didn't want to be Dumbledore's lapdog anymore and was going back to Voldemort. Look at the bigger picture though. I think that Dumbledore asked Snape to kill him because of the unbreakable vow and the curse blah de blah but also Snape is more valuable to the order. I think I hear your distant cries of "No! Snape is a traitor!" But Snape is valuable to the order. He is the only person who can get on to enemy lines, get information and come back alive. This is because of his cunning personality (and you wonder why they call then sneaky Slytherins) and the fact that he is a brilliant at Occulmency and Leglimency. So good in fact that the only people better than him are Dumbledore and Voldemort. Snape can get information and pass it on to the order (even though they don't trust him right now but all shall be revealed.) Now you are going to say that Voldemort can read minds so he'll be able to tell if Snape is lying. Remember Slughorn? The guy fiddled with his memory allbeit not a good fiddle but he fiddled. Snape a master of Occlumeny may be able to shall we say 'tweak' his memory a bit and tweak it a lot better than Slughorn can.
Pedwar
Dumbledore's death. Just before Snape and all them brown nosers burst into the tower, Dumbledore put a freezing spell onto Harry so that he couldn't move. Why? So that he wouldn't be the daft hero that he sometimes is and try to take on a lot of deatheaters by himself. Harry is also under the invisibility cloak remember so no one can see him. How come that Dumbledore managed to freeze him while he had the cloak on? Dumbledore can see through invisibitlity cloaks remember. Harry probably blames Snape for the freezing of his person, but hmm, unless Snape is Mad Eye Moody in disguise, it isn't going to happen.
Pump
Snape and Harry. Harry the loyal boy he is runs after Snape (what he's going to do to him, I have no idea. The boy may be good but he's not that good.) He calls Snape a coward and Snape goes off on one (excuse my very British language). Snape rounds on Harry and shouts "Don't call me a coward!" or something along those lines and runs off into the night with Draco. My first thought was "Snape is not evil because he could have killed Harry then and there for Voldemort." Then a very nice person pointed out the fact that Voldemort did not want anyone to kill Harry, he wanted to do it himself (the guy has no common sense, it would have been over a lot faster if someone like Malfoy had just walked up to him and AK'ed him there on the spot) but then I thought about it and realised that while Voldemort did not want anyone to kill Harry, he didn't say anything about someone capturing him and taking him back to Voldemort. Why didn't Snape kidnap him? Afterall, he had the perfect opportunity to.
Chwech
How is Snape ever going to be trusted by the order again if he is loyal to Dumbledore? My answer has two words. The portrait. At the end of the book it says that Dumbledore's portrait is put into the headmasters or shall I now say headmistresses office. You don't really think that Dumbledore is going to allow the order to keep on thinking that Snape is a murderer do you? Dumbledore, if anything, is a planner. He had the whole of the school year to gather his evidence in writing, through memories (the pensieve), and now, through the portrait.
You may now proceed to either A) Praise my brilliance, B) Offer me a job in the SAS, C) Discuss whether or not Snape IS infact innocent (I like a debate), or D) Give your whiny arsed opinion on how 'omg SNAPE is so EVIL!!22211"""'
At this point, the dogs will be let loose and you will be taken alive.
Stumble!