A Technical Evangelist is responsible for building and promoting technology in order to establish it as a technical standard in a market subjected to network effects. It covers things like building samples, product demos, and aiding the sales team. To be a technical Evangelist, you need to have a bachelor's or master's degree in computer science/ engineering with specialization in hardware and software systems. Companies like Novell, Microsoft, and Cisco also offers diplomas or certification courses for experienced IT professionals. I found a post from Thomas Lewis on 7 Tips to Become a Microsoft Technical Evangelist.