I've just come across a whole series of lectures on Roman architecture on academicearth.org, given earlier this year by Diana Kleiner of Yale. There are 23 lectures in total on a wide range of topics and sites and they include:
Habitats at Herculaneum and Early Roman Interior Decoration
Civic, Commercial and Religious Buildings of Pompeii
Houses and Villas at Pompeii
Exploring Special Subjects on Pompeian Walls
This looks like a fantastic resource.