I definitely benefited from reading other volunteers' application experiences throughout the application process, and wanted to post a quick run-down of my own application timeline to make my experience available to others. If you're not interested in the details of PC applications, feel free to skip this post!
From application to nomination, I found the process pretty quick and efficient. I started my application in mid-January (of 2009) and had all that information, along with references and the initial (online) medical questionnaire, turned in by early February. I received a follow-up packet with skills addenda, language questionnaire, background check form, and fingerprint cards the week after, and had that in (therefore officially completing my application) by February 24th. I had my interview (just under 2 hours) on March 4th and received an on-spot nomination for Sub-Saharan Africa, Agriculture extension, starting February 2010. So only about 6 weeks for that "leg" of the process. The fact that I was still in college for the application process probably helped speed things up, since the regional recruiter visited my campus.
Dealing with medical and dental was considerably less efficient and not fun, though doctors and dentists had as much to do with that as the Peace Corps. Dental was a nightmare for me--I ended up having to get about a million fillings for "weak spots" in my mouth, despite the fact I had gotten a clean bill of dental health at my last checkup 4 months prior. And had to pay for it all out of pocket since, really, who has dental insurance anymore? The PC Dental desk didn't really give me any guidance except to "follow my dentist's advice," and my dentist was hell-bent on filling every last almost-cavity--except, laughably, the one tooth that was actually sensitive. BAH. Anyway, most people probably won't encounter the same problems that I had with dental.
Medical was a pain, but as a disclaimer, I loathe doctor visits to begin with. The process is pretty extensive and took about 5 doctor's visits to complete, despite the fact that I was and continue to be (knock wood) totally healthy, with no medical file to speak of. Among other things, I had a complete physical, three blood tests, ear and eye tests, a TB (tuberculosis) test...you get the idea. A friend of mine, who was a few months ahead of me in the application process, had his physical returned for some nit-picky stuff (no "MD" attached to the signature, etc.) so I went over all the paperwork several times and irritated the nurses in the process by making them do more paperwork.
The PC gave me dental clearance in late April, almost immediately after I sent my paperwork in, and since my medical information was in the same packet, I wasn't too worried when that didn't immediately update online as received. So I was surprised when I received an email in early June, "gently reminding me" to submit my medical information, since they hadn't received it yet. Yipes! However, after speaking with a nice lady at the medical office, they found my misplaced file and updated it as received. In any case, definitely make copies of all the paperwork you send in--just in case.
At the end of July, I received a letter saying that my file was incomplete, with a solitary medical followup: they wanted an eyeglasses prescription. Now, I have not actually worn glasses since the 5th grade or so, and since I wasn't about to drop several hundred bucks on a new prescription and 2 pair of frames, I had gotten the nurse to sign off that I didn't need them. However, the fact that I had said on the initial questionnaire that I had worn glasses the the past meant they automatically asked for it. After some grumbling and calling up the medical office, I ended up sending in a personal medical statement describing the many ways in which I do NOT wear glasses. I do not need them in the car/I do not need them to see far/I do not need them to read and share/I do not need them anywhere. No, actually, the letter was much more professional (and less Dr. Seuss) than that! In any case, they gave me full medical clearance in early August, and I got my invitation about three months later, after much agonizing over its possible contents while it was in the mail.
Overall time from starting my application to finding out where I would be going: 10 months. A tad under 14 months from application to leave date.
Anyway, for people who are applying or thinking of applying:
~The medical process is pretty time- and money-consuming, so I would suggest being pretty sure of wanting to serve before investing in the whole process.
~Triple check every document you send in for completeness, and be prepared to make doctors and nurses do more paperwork than they want to. Yes, doctor, you DO need to sign there, and pretty please include your license number.
~All "negative" answers will probably come back to you in the form of more paperwork, so make sure they're correct.
~Make copies, make copies, make copies.
~It's going to take awhile. Be prepared to have (or at least feign) patience.
~The process depends on the person, so take all my above experiences with a grain of salt in regards to your own.
And if you want more information in addition to the official government site, you can find Peace Corps volunteer blogs here, and wiki content here.