In the Finder, navigate to the iPhoto Library, control-click and select Show Package Contents from the pop-up folder. Now create an alias for the Modified and/or Original folders within the package (your preference) and drag it/them to another folder on your drive.
In Adobe Bridge, navigate to the alias(es) and browse the directories as usual.
[robg adds: This solution should work for other programs that have difficulty peering into the new iPhoto library structure, but allow you to manually point to it via a file dialog.]

