How to use Services Basic Authentication?
The module authenticates a web service call against drupal accounts. 


Enable the module 
Setup a drupal user
Make the web service call with the credentials of the user.


Note that with basic auth, the credential can be intercepted if SSL isn't used. 

The module uses the standard PHP authentication headers and submits the standard drupal login form, without checking for any specific roles or permissions. So any drupal user will work.

Make a test web-service call with curl or wget to test it. There are also instructions in how to call with PHP in the call with curl stackoverflow answer.