Tracy Doolittle lives here in Sacramento and is just as much a fan of our beautiful old houses as I am. For $300, she'll do very extensive history on your home, finding out a timeline (and biographical highlights) of its past owners & residents, a permit history, the original property or historic neighborhood map, and other information - including, sometimes, historic photographs. She has also written a how-to article if you'd like to attempt this yourself.
A useful service, certainly. Tracy also has a website, Sacramento Historic House, which profiles several representative properties (including the beautiful and enormous Cranston-Geary house, in whose listing she gives a shout-out to us). Several of the most impressive Victorians are already listed, and it looks like she's adding new structures all the time. There's a blog, too, with many recent entries focusing on the historic homes and castles she encountered on a recent trip to London.