I found this really cool picture-transformer-thing via Little Birdie Secrets called Bakamatsu Koshashin Generator It allows you to upload a photo and then convert it so that it looks like it's been aged. It's a bit different than a sepia colouring program; the photos come out looking a bit more newspapery. The photos are supposed to come out in a style similar to old Japanese photographs, and I think this would work especially well on photos of architecture. I did a couple of photos; this first one of Alex and I did not turn out too well (as you can see I came out without a nose), but the next one of my bestest Evan and I turned out a lot better.
I definitely think I'll try this out again!