Traditionally, if you wanted to get audio for some writing or for a specific word, either it would be there or it wouldn't (and if not, you'd be out of luck unless you found someone to record something for you, which doesn't sound like much fun to me). Enter stage right: RhinoSpike. The idea behind RhinoSpike is pretty simple: (1) You submit text that you want to be read, (2) a native speaker records the audio for your text and uploads it to the site, and (3) you can then listen to the audio, download it, and use it for practice.
RhinoSpike was first covered by Tofugu in 2010, and still has a long way to go, but it can be a top-notch resource for any language-learner out there. I've tried the service out a bit, and it works well. I would recommend this resource mainly to beginner or intermediate learners of Japanese that would like to practice their reading and listening skills. You can read a full review on this resource here.