Do you listen to audio books? on CD or tape - or downloaded as digital files?  

Hi, I run a website that sells audio books for download. It only just started in December 2006 and it now picks up a few sales. I'd like to know from you readers if you have started to listen to audio books. I have a few additional questions:
- do you know that audio books exist
- have you ever listened to one (Samples of a few minutes can be listened to on my site)
- if you've listenend to audio books, did you download them or did you buy them on CD/ tape
- how many audio books have you read so far
- what topics/ categories interest you most?
A lot of questions, I know, but I'd like to get a feeling for the way the customers see this. Thanks for taking a few minutes to answer. My site can be found through my profile, just click on my name.