Hi Teacherman. Glad you are excited to start mustachifying your life. My advice isn't going to match most of the posts in this thread thus far. Hopefully you find these points valuable. I think there's some unbalanced and unthorough info being posted.
Ok, first, it's great that you are going to try commuting on bike. Hurray! You should absolutely try it. The cost of trying the bike commute is very low and the direct personal experience you will gain will far far outweigh any amount of information you read online.
Now, I'd like to say that you are setting yourself up for failure and disappointment. This change is too drastic and significant given your circumstances. There are many changes you could make in other areas of your life that would save you more money and not require the very high level of willpower and dedication taking on a 17 mile bike commute w/o distance biking experience. In short, I would rather see you rack up 3-5 smaller mustachian wins that in retrospect you can look back on and think "holy crap, that was so easy, I can't believe I didn't do that earlier". For example, after I canceled my landscaper and housecleaner, I never looked back. Mowing my lawn by push mower takes less than 20 minutes and saves me $50. It takes a long time on a bike to save $50 of gas.
Set yourself up for success. An attempted badass who fails and reverts to the old ways is not the goal here. Badassitiy has to be developed like a muscle like MMM says. You don't bench press your bodyweight on your first day at the gym. A 17m bike commute is too tall an order IMHO given you are still strengthening your badassity and frugality muscle. It's like if you tried to suddenly go from restaurant meals 20x a month to Early Retirement Extreme $80/month on groceries. Not going to happen. Not a good plan. Tackle a problem you can solve with a good balance of effort vs reward. Then tackle a slightly bigger one.
So my advice would be to drive/bus/carpool the bulk of your commute, say the first 12 miles, then switch to your bike for the last 5. Do that for a week, then gradually start biking further as you feel able. Biking there and driving back is a very good idea. Only trying this once or twice a week is also a good idea. Anything to give you more likelihood of long-term sustainability and positive change.
Some points based on my experience biking between 9 and 12 miles each way about 3-4 times a week for about a year.
Get good but cheap gear to start. Don't get anything fancy. You need personal experience to find out what you really need. I waited about a year before upgrading from a $20 headlight to a $175 headlight. I did the commute on a mountain bike with commuter tires for a few months before I finally got a real road bike. It was fine.
Take all the timing numbers you see in the posts here and completely erase them from your mind. Just time yourself. The numbers here seem off by a lot to me. I have very high physical fitness and can bike 20 miles without blinking an eye, but my 12-mile ride takes me a full solid hour. I am highly dubious that your 17-mile commute will ever be completed in the ballpark of an hour. People post better numbers, and maybe it's because I'm short and have short legs or something, but let me just say the timing numbers here look optimistic and not by a small amount. Tack on a significant amount of time on each end to deal with dressing and setup/teardown of gear. There are clothes to don, batteries to check, things to pack, etc. The changeover time does decrease with routine, but it's always going to be more than just hopping in the car.
Yes, your fitness will increase, but that's just a nice side-effect. There are ways to get much better overall fitness in far less time than riding a bike for 2+ hours a day.
Your time is valuable. Mustachian decisions often depend on the exact numbers. If line-drying your clothes took a week, it wouldn't be nearly as compelling. 2 hours is a good portion of your waking day. If you love your ride, hurray, more power to you, but perhaps there are other more enjoyable things you could be doing with that time than riding alone on your bike.
Hedonic adaption works both ways. You may miss your car in the beginning, but soon enough you will like the ride. I particularly enjoy my nighttime return trip rides with the roads to myself and the moon shining down. I've also made myself almost allergic to driving with even the tiniest bit of traffic. It is now infuriating after enjoying the free-riding bike ride. However, just like grinding away in a car commute month after month gets old pretty darn quick, riding for an hour can be every bit as tedious and annoying. It's not some magical fun machine when you have a lot to get done that day and it's cold and you just want to get where you are going already.
Hopefully this tempers the exuberance of the thread a bit. Start small. Win small.