Sadly this promptly removes all MP3 players that are on the market. Almost no player allows you to install software (on the player.)
Bob
I am interested in buying an MP3 player primarily for listening to audio books during my daily commute and also for soring music. Here are the three criteria that are importnat:
1. 30 GB or more storage
2. Compatible with either MAC or PC operating systems
3. Can accept non-proprietary software for playing audio books. (i.e. I understand that iPod and Zune won't fit the bill).
Does something like this exist?

Chowhound
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GameSpot
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TechRepublic