I am currently trying to overlay old maps onto modern Google Earth images. This works moderately well, but I really could do with some help understanding Google Eath's instructions, as I am getting mixed results.
When it does work, it is an extremely powerful tool.
Overlaying antique maps was exactly what I was doing when I decided to start Tadmap. It's good to see that other people are looking for the same thing.
I haven't been able to add any new features to Tadmap in a while but I have been working hard. There have been some problems with uploading high-resolution images but I'm nearly there.