Employees are first hired as Postal Support Employees. They need to take a test and interview. Postal Support Employees can be converted to full-time regulars
I applied online. I interviewed at US Postal Service in Mar 2011
Interview
Two interviews- one over the phone and one on site. A lot of testing. Beat out the other contestants and your in. Also- make sure your answers are consistent with the fact that you can and will drop everything to get to work and will be there quickly.
You go through the testing process and get called to a mass interview session. The questions are basic, and they give you their answer about being recommended (i.e. hired).