Stan

1000camels

This plugin renders an audio player and playlist for all audio elements within a page. It pulls together audio files listed in posts (typically in the excerpts in posts) and provide a single player to control them. It also keeps track of the play point and can even continue to play the audio on subsequent pages that it is listed on.

Audio Envelope

This plugin creates a player and playlist from all audio elements on the page.

aueda

This is a simple, cross platform, accessible audio player.
(Basic usage) 
Write a shortcode like the following:
[esplayer url=”http://example.com/wp-content/uploads/sample.mp3″ width=”200″ height=”25″]
For more details, please see the document from the following URL: 
http://tempspace.net/plugins/?page_id=4
This audio player has three different modes:
(1)Simple mode 
What the player has is only a play-button. Or when its width is specified as greater than 2x of height, a positioning slider is displayed.
(2)Image mode 
When an image on the wordpress page or post is clicked, specified music begins playing.
(3)Slideshow mode 
Playing slideshow and music. Timings of changing images are specified in an timetable.
I tested this plugin with IE8,Chrome,Firefox,Opera,Safari(WindowsXP), IE9(Windows7), iPod touch(iOS 4.3.5), and Android(2.3, emulator).
This audio player has accessibility features.
<ul>
<li>Text browser users can download audio file. </li>
<li>Screen reader users can manipulate the player by selecting play button, stop button, etc. </li>
</ul>
You can enable or disable these feature in the admin page. I tested them with Microsoft Narrator, JAWS(demo version), Focus Talk(demo version) , ALTAIR and NVDA.

EsAudioPlayer

This is a simple, cross-browser, accessible audio player (MP3 player) plugin.

Audio Envelope vs EsAudioPlayer