Get started bike commuting, no fuss
scope your route - How far is it to work? Less than 10 miles? No problem! The best route by bike may be different than by car. Get a map (or download Google Earth for free), look for local trails or check out your route beforehand by car. Know where you're going and how far it is.
get a bike - You don't need a fancy bike to try it out. I started commuting on a mountain bike, after I fell in love, I graduated to a cheap-but-good used road bike that I still love. Use what you've got, or borrow a bike from a friend. If you stick with it, reward yourself by buying a nice bike. You can easily afford a decent bike with only a couple month's saved car/gas money. More about choosing a bike here.
set a goal - Set an easy goal and stick with it. Maybe plan on biking to work only 2 or 3 days per week for a month. See what happens! If you're committed, you can do it, and you'll probably fall into an easy groove and do even more. If you're not committed, it's easy to give in. I sold my car, so the decision for me is very easy every day because it's my only choice! Maybe leave your car at a friends house for a week - you'll see that once the decision is made, the biking part is easy.
get ready the night before - Make up your mind to ride the night before. if you try to decide in the morning, you'll never do it! Set out all your stuff, work clothes, shoes, etc. Stick to your plan even if you don't feel like it in the morning. You'll feel better once you're on the bike - I promise! Making up your mind is the hardest part. And it only gets easier. Plan accordingly so you can get to work a little early at first, leave yourself time to wash up and change. Reward yourself with a trip to Starbucks, you can afford the calories and the money!
do the math - I like to know how much money I'm saving every day. When I know that every time I get on my bike it's another $30 in my pocket, I feel pretty good about doing it. Add up your own savings here.
Eliminate sweat - If you have a shower at work, no problem. Maybe there is a gym nearby. If not, a simple washcloth at the sink in the bathroom is all you need. I find that a quick wipe-off with a damp washcloth (no soap) and a little anti-perspirant leaves me feeling fresh all day. And it only takes about 5 minutes. Arrive early for extra privacy if you use a public restroom. More ideas on Sweat & Showers.
More Info - Check out the Overcoming Common Obstacles Page for more info on some of the things that can seem daunting at first.
go for it - That's it, get on the bike and give it a try. You can decide later if you prefer saddle bags to a backpack, or what kind of shoes to wear. Give it a try in good weather and you'll get your route and timing down - and deal with rain gear later. Make it easy the first few times, before you know it, you'll be a pro, and you'll be back here on this website, offering tips for other new riders. Have fun!