The Russian Record: Sergei Mikhailovich Prokudin-Gorskii - pre-WW I composite color images. Seems to have more/different photos than The Empire That Was Russia which I've linked before. [via Metafilter]

Update:
122 color images listed here [via the older Metafilter thread]

Update 2:
And then there's this site. [via another Metafilter thread]