Change the year of 500+ photos in iPhoto
In iPhoto '09 (or later, I believe)...
- Select all the photos with incorrect dates
- In the menu bar, select Photos -> Adjust Date and Time
- Modify the date to reflect the change you want -- for example, to shift all the photos forward one year, increment just the year part of the date by 1
- All the photos will be time-shifted by the relative change you specified