can play audio files but can't bookmark, how about...

[Pangolin]

....pod casts.

If you've got the ability to transfer MP3s, prefer your audio to be talk rather than music and are frustrated because you can't bookmark where you are in an audio book, then check out the BBC's podcasts. (noooo, I don't work for them - just a fan)

Fifteen mins or half an hour will probably a bite sized chunk and you won't need to bookmark. Just an idea, I've been a complete addict for years...

For two personal faves check out:
http://www.bbc.co.uk/podcasts/series/ahow/all

and:
http://www.bbc.co.uk/podcasts/series/iot

all under one roof, (radio 4 and 7 are talk radio, Radio 3 classical and world music and some interesting documentaries:
http://www.bbc.co.uk/podcasts/

From iTunes, the History of Rome is splendid too. Or their site:
http://thehistoryofrome.typepad.com/

enjoy