So you decided to pick up cycling I'm happy for you - here are some tips to get you started. This is a work in progress so check back from time to time as I'm constantly updating this page.
Obviously you need a bike. There are a myriad of choices out there and your local bike shop (LBS) can help you choose one. Get a bike that fits you, meaning, the knowledgeable bike shop sales person should be able to pick the right size bike for you and adjust it just before you pay for it. Choosing which make & model to get is a matter of personal choice. My advice is to do some research, read cycling magazines, talk to veteran cyclists, and visit your LBS. Choose a bike that will suit your needs now and in the future. Don't be afraid to that you're a beginner - there's absolutely nothing wrong with that.
Helmet - a good helmet should first be ANSI certified. Don't worry, all helmets being sold in the US are certified. Pick one out that is well vented and perhaps a color that's neutral or would match your cycling clothes ( You do have to ride in style..). Personally, I like white because of two main reasons, one, it reflects sunlight, meaning it's cooler. Two, it's highly visible.
Clothing (Shorts) - Don't go cheap on this one, you will thank me for it. Get the best padding your wallet can afford. There's a ton of choices out there depending on your budget. (Jerseys) - Get one that's comfortable to wear, meaning snug and has a long and durable zipper. (Shoes) - these are perhaps one of the more important investment you need to consider. At this time you're probably debating if your going to go clipless or not. Well, you should go clipless, if you're still terrified of the idea, don't worry, it's OK, you will learn and you will eventually gain confidence. Good brands include SIDI, Shimano, Louis Garneau, etc.
There's a triad in training I personally practice: Training - Rest - Nutrition. Lack in either one and you will get nowhere. It's simple - first you create an "overload" - Training, then allow your body to adapt - Rest, and lastly give it fuel - Nutrition, in order to build & repair your engine for leaner faster you.
There are a lot of books out there you can use to help you create structure in your training. I personally like Joe Friel's "The Racing Bible" - even though your goal may or may not be racing, getting to know "how to train right" saves you time and money. You can also hire a coach if you have the dough to spend. Nevertheless, start by making a plan or setting a goal for yourself. In H Town, the annual MS Ride to Austin is a good one. A plan will help you focus in the long run and prevents you from wandering aimlessly til you loose interest in the sport