It seems people tend to see accessibility as a nice bonus, but nowhere near mission critical. This is especially true when we compare the relative importance of accessibility and SEO. But what people forget is that search bots are a little bit like screenreaders. Accessibility is not only helping your visitors with disabilities, but it will help search bots to make sense of your site and to find your content.
I’ve been saying for a long time that "Google is the largest blind user on the internet" for a few years. Many people are also using that, to the point that for those of us in the accessibility world, the saying has turned somewhat trite and cliché. But recently on the Mambo forum, I used it and had several people thank me for explaining it to them in such a way.
If you design the content of the site to be semantically correct, use proper document structure (use of hierarchical headers, etc), and generally ensure your content is accessible, you’ll make the life of screenreader users much easier. You will also make it easier for Google and other search engine to crawl the site, make sense of your pages, and list you appropriately.
Of course, nothing’s guaranteed, but you’ll help your chances. And every little bit helps!