Last Updated: Oct 30, 2015 Views: 20
The ProQuest web site has a number of FAQs that answer many questions about publishing your dissertation.
Here's what their FAQs has to say about how long it takes for a dissertation to be available once submitted:
After you submit your manuscript, it must be approved by your graduate school before the site administrator sends it to ProQuest/UMI Dissertation Publishing. Once we receive the manuscript from your school, it can take 8-12 weeks before it is available online.
(Retreived from http://www.etdadmin.com/cgi-bin/main/faq?siteId=13#general1)
Check out the links above for more information.