Must apply online via the US jobs website. If you meet the qualifications and are asked to interview, you then complete two additional pages with general information and given an interview time. Then they call you. It is a single interview via telephone.
Interviewer was a Supervisory Patent Examiner (SPE). Interviewer was very cordial, despite calling my office number (listed on one document) before reaching me on my cell phone (listed on interview document). The interviewer was warm, described his previous work experience (more than one decade at USPTO, also an attorney). Since I had already taken and passed the USPTO registration examination ("patent bar"), he did not bother with asking about "general IP" questions or "what is the role of the USPTO that I saw others were asked from their reviews here on glassdoor. While we chatted about his background, we discussed general IP topics, such as reading Patently-O blog, and how much of a mess the opinion in Prometheus must make / will make for patent practitioners on both sides of prosecution.
The interviewer did inquire about the other regular questions already listed on glassdoor, such as "Describe a time when you were explaining technical something-or-other to nontechnical audience" and "When you have multiple tasks to complete, how do you get them all done".
There were also the basic interview questions related to "tell me about a time you had to work with someone difficult", which lead into "tell me about a time you had to persuade someone".
I had the opportunity to ask about things I was interested in, such as the hoteling program. He asked me which art unit (or general "field of technology") I would be most interested in, and what my second choice would be, if any. He also asked "if offered a position, what would be your earliest availability" - to which I replied "as quickly as possible, but since I'm located in the Southeast and currently work as an attorney, a realistic approximation would be about 4 weeks, giving me time to wind-up any open assignments with my current employer, pack up my things, locate a suitable place to live in the Greater-D.C. / Alexandria area, then move-and-settle-in."
I was told I would hear something back in approximately 1.5mo. I'm actually very interested in working at the PTO, so I hope that I'm among the 1,500 candidates that are selected.