I went through the State Dept. hiring process before as well. The stages are fairly similar with the exception of the Foreign Service Officer Test (FSOT) being the first step to the process. I was eliminated at the Oral Assessment (OA) phase. But if you pass the OA, then it's pretty much the same as USAID in regards to obtaining clearances.
Everything with State begins at their website. Actually, the whole process is outlined very clearly there!
Instead of picking a specific position or backstop, State's positions are a bit more general. State has 5 main career ladders or "cones". Every cone though will have to do a tour or two doing Consular work which means working Visas for people wanting to come to the US or assisting Americans abroad even if they are not in the "Consular" cone.
FSOT & Language Test
While filling in your basic information in the application, you will also have the opportunity to indicate whether you have any language capabilities. After completing the application, you have to select a test date to take the FSOT. The test reminds me of the ACT or GMAT in that you'll take it in one of the various testing centers where they hold those tests. Even more similar is that like those other standardized tests, they even offer an official test preparation guide! http://www.act.org/fsot/.
After taking the test, if you indicated you had a language skill, you may be requested to do an over the phone language test as you will receive bonus points to your score in the very end if you pass the OA. I believe this is only done if you indicate a language ability for one of their critical priority languages (ie. Chinese Mandarin, Arabic). The test will involve you, the tester, and a listener. You will then basically have a conversation with the tester and based off of how you can communicate they will indicate a rating and add that to your candidate file (http://www.govtilr.org/).
Qualifications Evaluation Panel (QEP)
If you successfully pass the FSOT, you will be invited to the QEP stage. Basically, it's like the original application with USAID. There will be various questions on your experience and you will be prompted to provide a short answer response on that. After providing your response to these questions, then your file is sent to the Board of Examiners (BEX) and they will categorize you based off your selected cone and review candidate profiles based off their QEP responses, their FSOT score, language proficiency, etc. Basically, like reviewing an application but they have a lot more information to use in their determination. This will take another month or two until results from this are released.
Oral Assessment (OA)
The structure of this in-person interview is similar to USAID. There are three components being the Group Exercise, Case Study, and Structured Interview. One marked difference is that candidates from all different cones are assessed together in State rather than USAID which evaluates candidates of a similar position together. After the day of testing is complete, State provides immediate feedback of whether you will move on or not. Candidates will be placed in a room and called out. If you are not successful, you will be greeted by two of the examiners and be given a file with your results for the day and be given the chance to ask any questions. I was at least pleased that in the file they gave me, they noted I passed the over the phone language test for Mandarin.
If you are successful, then you will begin the clearance process and eventually be placed on a register for eligible hires. A good group that discusses the OA can be found at this address: http://groups.yahoo.com/group/fsoa/
Submitted application to take FSOT.
Took the FSOT.
Received confirmation of passing the FSOT and invitation to submit narratives for QEP.
Scheduled and took phone language test for Mandarin.
Received confirmation of passing QEP.
Registered to take the FSOA.
Took the FSOA in DC.
*Disclaimer: If any of this violates the Non-disclosure Agreement, please let me know and I will remove. To the best of my knowledge, the posting contains general information readily available at the State Department website or is generic in nature for disclosure*