Thanks for the recommendations from the PodCast crew. Cut and paste is exactly what I've been doing for a while. I've got a simple text file with a bunch of standard responses. Things like a link to the dining reviews, resort maps, height requirements, the location of the nearest [fill in the blank].
The only problem with that solution is that you have to switch back and forth between applications. With a browser add-on I'd be able to stay in Safari or Firefox and just hit the appropriate key to respond.