Free audio hosting is more difficult to find. However, you'll find it at Chirbit. It accepts MP3, M4A and WAV formats. The size limit is 120MB per file.
This allows two hours of MP3 and M4A audio per file. WAV will only get ten minutes. You can always convert WAV files to MP3 or M4A. Zamzar is a good place to start.
To use Chirbit, create an account. Then, upload your audio files. You'll see them on Chirbit's server. A link will appear below each file. Click the link and select a blogging program. This will be whatever you're using. Most blogging programs are included.
Enter your blog address, along with your user name and password. Write your blog post in the Chirbit interface. The post and audio player are published to your blog.