Spoken Freely Presents Summer Shorts 14" to your list of audiobook sources. (I started the list here: in "LISTEN UP! June is Audiobook Month".)
Here's the first paragraph from the Spoken Freely website:
The audiobook community is giving back! Spoken Freely, a group of more than 40 professional narrators, has teamed with Going Public and Tantor Media to celebrate June is Audiobook Month (JIAM) by offering Summer Shorts ’14, an audio collection of poetry, short stories and essays. All proceeds from sales of the collection will go to ProLiteracy, a national literacy outreach and advocacy organization.
Visit the Spoken Freely/Going Public website for more details, including the release schedule and associated links.