Download the snapshot of Opera 7.60 Preview 1 and take the speech capabilities of this beta version for a spin.
This release comes with a set of voice libraries that enable the user to control Opera by speaking commands to it. Opera now supports XHTML+Voice 1.2 and the CSS3 speech module properties new to CSS3 are prefixed by-xv-). With the default setup, you can navigate pages, have selected text read to you, and control parts of the browser.
Personally I had little success with getting the voice recognition to work reliably - despite my efforts to put on a passable american accent - but it’s certainly an intriguing new feature, and I can see XHTML+Voice becoming a valuable addition to any accessibility minded developer’s set of tools.