On what to do with retractions
PLOS has this report from COPE, (Which stands for Committee on publication Ethics) latest meeting. The report spends some time talking about how to deal with retractions and corrections to already published science. Also, there is a link to COPE’s homepage. They do maintain a database on retractions and corrections that, from what I can gather, is searchable.
And, of course, make sure you have a link to Retraction Watch.