Ok! Screw whatever site I used to use, and I don't feel like embedding the images again, so here's an imgur gallery containing all the blueprints:
http://imgur.com/a/FVFlYKeep in mind, some of those pictures are from before the 1837 fire, and some are from after. The captions provide dates and english descriptions, usually. Also, some are upside down, sorry!
Here's some highlights from the gallery:

the hexagonal telegraph tower

the neogothic library

rotunda cutaway

basement kitchen plans

opera house cutaway in southwest corner

some of Rastrelli's early variations for the floor plan
These are all from the 1990 book, ISBN 5-274-00375-3
It's all in russian, but if you can read russian I'd highly recommend getting a copy!