Monoblog is a widget plugin that allows recordings of you reading your blogs aloud for the seeing/reading impaired or for people on the go.
If you so choose, this plugin can also generate an audio podcast of your Monoblog content.
Check out OwnTheNarrative.com for more information and examples.
After activating, while still in the admin panel, go to Appearance->Widgets. Then click and drag the Monoblog widget to whatever sidebar/area you want. NOTE: The sidebar/widget area must be visible in your posts in order for this to work.