The Lonely Planet Travel Guides for the Amazon Kindle eBook Reader have Text-to-Speech enabled. Examples are Lonely Planet France (Country Guide) and Ireland. These might be of use for people with reading difficulties. However, I am not sure how well the text oriented interface of the older monochrome Kindles would be, or the dense text-oriented format of the Lonely Planet guides.
Lonely Planet experimented with Mobile XHTML to provide travel guides on phones, way back in 2005 (I was teaching mobile web design to university students). The results at that stage were disappointing and Lonely Planet discontinued that service. But they now have Lonely Planet Apps and eBooks.
Also there is the Apple Siri voice interface for Apple iPad/iPhone.