M_Catalano,

I would recommend a training session called Power Talk. We had a similar situation with a salesperson who was highly introverted. After attending this session this individuals sales sky rocketed!

The course was designed by an actor so the techniques are VERY different. However, I was extremely impressed with the difference it made in the individual.

As crazy as this may sound, you might also recommend the person take improv lessons. This allows them to learn the ability to think quick on their feet and make a connection with their 'audience'.