There should be a feature added soon where users can submit corrections right from an album page. This will make it much easier to keep track of requested changes, and users will know exactly how they can request changes.
For the time being, posting in the "Error Reviews" thread (http://forums.albumoftheyear.org/t/errors-reviews/50/) or emailing would be the best way to submit corrections. I like to think that I see most requests, but I'm sure there have been some that I've missed. I'll try to keep track of these better in the meantime.
I don't think opening up editing to users would be the best step for the site right now. This would make it much harder for me to monitor the data as things could be edited constantly. There may be a delay on things getting updated right now, but I think the integrity of the data is much stronger under this scenario.