I didn't know JT called into the Art Bell show. You might try contacting Pamela. She was in the middle of the whole JT thing. She would know if there was an audio, and where it would be available, if at all.
I have a transcript of what was said: Art Bell reads a FAX sent by Titor in April, 1998. There were two FAXs, actually. Bell doesn't contribute much to the story except insofar as it was show where Titor debuted, and his forum where he first posted.