Hey! Do you guys know about EThOS? That akward looking acronym stands for Electronic Theses Online Service, and it does pretty much what it sounds like: it lets you search for British theses and download pdfs...FOR FREE! It's pretty handy, actually. I recently had a doozy of a time trying to get some unpublished PhD dissertations out of Aberdeen, for instance. With this, though, it seems to be pretty easy to quickly search out and download documents.
You have to register, but it's free, and it seems to have a lot of geo-science related theses up and available...AND if they don't have a particular one, you can put in a request and they'll get it scanned for you (probably by some Cockney street-urchin wearing a lot of Houndstooth, I reckon). Pretty handy, actually.