There is a bit of controversy around the blogosphere about a papal decree for the year of St. Paul and the plenary indulgences that Benedict XVI is offering.
I think there's some misunderstanding as to what this is. Pope Benedict isn't reinstating some Medieval relic...Indulgences never left. Pope Benedict XV gave a partial or plenary indulgence for Bible reading with his papal encyclial Spiritus Paraclitus in the 1920's. Trent reaffirms this dogma immediately after Luther's shenanigans, etc. This isn't something that Benedict XVI is digging back up, it has been part of the Church's teaching and life for quite some time.
Secondly, Indulgences do not forgive sins. Indulgences are for the remission of temporal punishment due to sin and are only given after the penitent has received the sacrament of reconciliation. You may not buy an Indulgence, either.