I just did this last week.
It was the Buffalo office but I would think its the same everywhere.
You should get a letter from your employer, It may not be required but a good idea. I made my appointment over the phone with their automated system, That part took about 10 min. I didn't want to make it online as they ask for a date for international travel and didn't want to lie.
Show up to the passport office with all your required paperwork, you will need to get a passport photo taken BEFORE you arrive, many drug stores can do this, a google search will help, I found a coupon for Rite Aid, got the picture for $7. I was at the office for maybe 15-20 min, you will have to pay the passport fee $110, and the expedite fee $60. Go in the morning and you can then wait till the afternoon (3pm at the BUF office) and get a new passport the same day, or they can mail it by snail mail you'll have it in a few days, or you can have it overnighted for $15.95 and will it will ship out the next business day.
Overall it was a pretty painless process but if you want/need it quick it's the only way.
Also for $30 more you can get a passport card, it won't work for clearing customs by air travel, you will still need the book for that, but I keep it with my ID badge holder, a little more convenient for getting thru TSA IMO.