Here are some with strong evidence of innocence and some that were pardoned posthumously many years after their executions. I believe there are probably more than those mentioned on this page:
http://www.deathpenaltyinfo.org/executed-possibly-innocent
Carlos DeLuna, very interesting case....a long time sledgehammer for the anti dp crowd. Problem is, it's all bunk.
Just in case you don't know about appeals, I'll give you a short-short version. When you are convicted of murder and given the death penalty you start your appeals with the direct appeal.
This appeal deals solely with procedural or legal errors in your case...like a juror being excused for unlawful reasons or the judge interpreted the law wrong or even read the jury instructions wrong. That appeals goes from the state, to the circuit court and, possibly, to the Supreme Court.
Next is the writ or habeas corpus appeal which deals with Constitutional errors in the murder trial. Things like ineffective counsel, self incrimination, speedy trial, etc. This goes the same path...state, circuit court and, possibly, the Supreme Court. This is also the time to bring up a new witness or evidence of actual innocence, like someone else confessing to the crime.
I've read DeLuna's writ appeal, it says
nothing about a witness or confession from someone else. Which means the claims by the reporters, etc. didn't hold up to scrutiny (but sure make a nice story)
http://ftp.resource.org/courts.gov/c/F2/873/873.F2d.757.88-2613.html
With Ruben Cantu, the issue of the identification was all over both his direct and writ appeals...and the courts found his arguments without merit. So whether the anti dp crowd likes it or not, this was a fairly judged case.
http://bulk.resource.org/courts.gov/c/F2/967/967.F2d.1006.91-5512.html
And the Larry Griffin links are the most blatant attempt at manipulation I've seen in a long time - completely one sided.
http://law.justia.com/cases/federal/appellate-courts/F2/946/1356/421842/
With Joseph O'Dell we get half of the story...as usual. There was overwhelming evidence O'Dell committed murder and rape, including a confession, but the focus on one part of the evidence is a typical trick.
The DNA is addressed in points 152-180
http://law.justia.com/cases/federal/appellate-courts/F3/95/1214/547098/
David Spence is innocent because of two opinions? And the basis they give, the "for hire" murder, applied to only one of the victims...there were three! Give me a break! There were co conspirators and he confessed to two people. Also, there was odontology evidence.
http://law.justia.com/cases/federal/appellate-courts/F3/80/989/627569/
Leo Jones basis his claims of innocence on the dismissal of the police in his case years later and late breaking eyewitnesses. The most hackneyed and overused claim for innocence! Like someone else's conduct years later proves you were innocent, ridiculous!
http://law.justia.com/cases/federal/appellate-courts/F3/80/989/627569/
Can I say I'm sick of hearing about Gary Graham? Lord that man is a bad penny...
http://law.justia.com/cases/federal/appellate-courts/F2/950/1009/110579/
Let's have a little balance to this case and present the pro death penalty's site on the Graham case:
http://www.prodeathpenalty.com/graham.htm
Claude Jones - all puff and no smoke, much less fire! The basis for innocence is that the hair that tied Jones to the murder was denied mito DNA testing, so that obviously means he's innocent. Whatever
Interesting they tried to tie Willis to Willingham.
http://courtlistener.com/ca5/9Zm/willingham-v-cockrell/