Link Repository of International Dissertations This question (cry for help?) grew out of Colin Tan's question: does anyone have a copy of schmid’s effective work on hilbert 17th? which was a request for a copy of an Habilitationsschrift.
We've all been in this situation: somebody works on a dissertation of some kind, obtains interesting results, but either can't be bothered to publish because they're leaving the profession, or do publish the essentials, but have to omit some important details because of space considerations.
Inter-library loan can be an option in these cases, but it's very likely to take a very long time if it works at all. In the US, it appears that most universities require you to sign away your reproduction right to an independent company which will keep your dissertation on microfilm (correct me if I'm wrong, this is CW after all!). So in that case, you can track down a copy of the dissertation in question (if you're willing to pay for it) -- that is, if you can manage to track down the reproduction service in question.
Some countries, on the other hand, feel the need to maintain an online  repository of the student work done in their universities. Here again, it involves a non-trivial slog through various library links before finding the right place (and may demand a better command of the language than for math reading). Hence, the question, which is more of a suggestion:

How about we gather a list of links to various dissertation repositories / reproduction services right here?

Suggestion: Since no answer is "better" than any other, and to improve readability, it would be best to keep this to a single list answer that can be edited with the various contributions. Thanks in advance!
 A: Stony Brook has a thesis server for theses in dynamical systems (not necessarily written at Stony Brook):
http://www.math.sunysb.edu/dynamics/theses/index.html
The files are available for the years 1990-2009 (39 total).
A: Thèses de l’entre-deux-guerres (ordre alphabétique) : 1913-1947.
Thèses de l’entre-deux-guerres (tri par année) : 1913-1947.
A: Some other German site: http://www.sub.uni-goettingen.de/ssgfi/mathdiss/
And, for what it's worth, abstracts of recent dissertations from Moscow University (in Russian): http://mech.math.msu.su/~snark/index.cgi?data=newstape&menu=index&head=index
A: For Greece, try at the National Archive of PhD Theses.
A: Here is the list:


*

*France: all (sufficiently recent) theses, although I believe the authors are supposed to submit them, so there may be some missing. http://tel.archives-ouvertes.fr/

*United States: most (many? sufficiently recent?) theses are available through UMI ProQuest. They are slightly annoying in that you can use one link if your library subscribes to ProQuest (http://proquest.umi.com/login) and a different one if it doesn't (http://www.proquest.com/en-US/products/dissertations/disexpress.shtml).

*ETH Zurich has its own database of Master, PhD, and PostDoc dissertations.


Further links from the mathphysicist's answer:


*

*Germany: http://search.dissonline.de/

*Canada: http://www.collectionscanada.gc.ca/thesescanada/

*Spain (at least some universities): http://www.tesisenxarxa.net/

*Pan-European (DART): http://www.dart-europe.eu/basic-search.php
A: For Canada, see the Theses Canada website.
In the US, a number of universities have their own repositories where the theses are often available free of charge (unlike ProQuest which requires subscription).
Example: MIT DSpace (for mathematics theses, see here)
For Germany, see dissonline.de
For Spain (covers many but not all Spansih universities), see tesisenxarxa.net
There is also a pan-European e-theses depositary DART.
Also there is a useful worldwide list Online Theses in Number Theory
