I know people are very opinionated on these books, but Cushman has rallied some notables to assist with the first audiobook...
http://www.jacobsbrownmediagroup.com/audiobook---these-are-the-voyages.html
The principle reader is Vic Mignogna (Captain Kirk in the web series, "Star Trek Continues"). Other guest performers include Adam Nimoy, reading the quotes and letters of his father, Leonard; Chris Doohan (Scotty on "Star Trek Continues), reading the quotes from his father, James; Rod Roddenberry, son of Star Trek creator/producer Gene; and other Star Trek alumni, such as DC Fontana, reading her own memos from 1966-67. Part 1 comprises the first 18 chapters of the Season One book (ie. 13h 58m of a total 28 hours) via streaming audio.