I recommend: Writing Excuses

Writing Excuses is a podcast about writing and in particularly genre fiction (such as fantasy, sci-fi and horror). The 'cast is done by Brandon Sanderson (Elantris, Mistborn, finishing Wheel of Time), Howard Tayler (webcomic Schlock Mercenary), Dan Wells (I'm Not A Serial Killer series) and Mary Robinette Kowal (Shade of Milk and Honey).

While it is about writing and doesn't directly translate to RP, I think it's still useful for the MMO RPer. The episode I'm going to link to is specifically about character motivations, in the beginning and then later in the story.

Give it a listen. Each episode is just circa 15 mins long.

Writing Excuses 6.2: Internal Motivations

Ooh I'm going to love this.

Thanks a load for sharing!