UKZN libraries keep one print copy of every thesis submitted through the university (search the iLink catalogue for details) and upload an e copy onto ResearchSpace. For earlier theses not yet digitised, there is a loanable copy.
Up until recently, theses were only available in printed form. Now, libraries are digitising their theses. At UKZN the digitised theses are accessible via ResearchSpace. You can search for a thesis by author, title, subject or community. UKZN is slowly digitising theses submitted prior to 1999. Access to the online pdf of a thesis is also possible via the iLink catalogue.
When accessing theses from off campus, be sure to access via Firefox.
There is no consolidated international index of theses, but theses can be located via Google Scholar or, try the website of the institution through which the thesis was done.
South Africa
Note that these collections do not generally provide full text access, you will need to go to the relevant institutional website and see if its available.
International
See the page of theses collections on the Library's website