I am convinced that Mumia is innocent, not that there is reasonable doubt or whatever, but that he is in fact completely innocent. That's a matter of opinion, ones can draw their own from looking at the available evidence. Some other time I'll try to come forward with a comprehensive list of the various sites/sources ones can check out regarding this.
To I, the case raises a different issue to the ones you mentioned, rasi: to I it raises the issue that if he HAD been "guilty" that would make him just as much a hero in my eyes as he is in this world where I am virtually certain he is innocent. Why should we accept their definitions of what a criminal is? To I, if you defend your family from vicious attack by whoever, by any means necessary, that makes you a hero not a villain. The police themselves don't dispute the fact that Officer Faulkner was smashing Mumia's brother repeatedly in the head with a metal flashlight, i.e. a potential instrument of murder.
As for Barack pardoning Mumia... sorry to say I think there's about as much chance of that as Barack withdrawing all troops from Iraq within four years, i.e. nil. Rememeber he actually promised to do that, now it's clear he won't as us "naysayers" were saying from the get go. He has never promised or so much as hinted that he would free Mumia or any other political prisoner, in fact he has made few if any promises of any kind to Black people since he was taking the Black vote for granted anyway.
Mumia's best hope is for a new trial, and failing that, people mobilising to bust him out Assata Shakur style... once all legal recourses have been exhausted.
Of course if in four years time Barack does turn out to have been some kind of undercover revolutionary after all I will eat my words, but frankly I think the chance of the moon turning out to be actually made of green cheese is higher.
PS I put up this interview on audio from youtube, if you scroll down enough you'll find it, if you want to hear Mumia's voice directly.