Step 1, find the local MSF courses, register and attend. You need to make sure you are capable of riding a motorcycle before you buy one. Also, passing the course in most states qualifies you for the Motorcycle endorsement on your license, meaning you don't have to take the DMV test. You are required to bring a helmet long pants and appropriate footwear to the MSF class.
Step 2, decide what sort of bike you want. There are 3 types, Sport, Standard, and Cruiser. Try and think about how you want to use the bike. Many people only want to ride on weekends, some for their daily commute. You'll want something that is comfortable, meets your standards as far as the mechanics of the bike, and of course, something you like looking at.
Step 3, gear. Protective and if you plan on doing maintenance. As far as helmets go, try and get something that is both Snell and DOT rated. Those are the two tests that helmet manufactures perform on helmets. Some helmets have no safety endorsements, the best have both. Your helmet is the most important piece of safety equipment, so don't skimp. Gloves and boots, Jacket and pants. Good good strong gloves and boots, they aren't just for looks. As far as jacket and pants, there are a lot of debates with regards to leather vs textile...but really they come up about even. One is slightly better with abrasion resistance, and the other slightly better with tearing resistance. Just get one.
As far as purchasing goes. If you go to a dealership, you are not able to test drive a new motorcycle. You are allowed, however...to climb on and sit on it for as long as you like. Do this, make sure you will be comfortable. Move the handlebars from far left to far right and make sure you won't be hitting yourself in the kneecaps, etc. If you buy used, you will probably be allowed to start it up, each purchase will be different.
Bike size, this is a largely debated item as well. Most people agree anything in the 600cc range and below is good learning material. Some insist on the 250cc range, but some people feel the need to have a bigger bike real fast and therefore disagree with the 250 recommendation. You'll have a better idea after your MSF class. Most MSF classes use Honda Nighthawks and Rebels in both 250 and 500 ranges (at least everywhere that I've been able to find). You may go into class thinking you need a 650, and come out being happy with a 500. I personally plan on going with a 250cc and riding it as long as I can. A main incentive for me is the ~65mpg the bike runs at, though.
As far as mechanics there are two basic types of motorcycle engines/drive systems. The V-Twin/belt drive, and the inline/chain drive. You'll find the v-twin on cruisers and some standard type bikes. the v-twin will be geared more towards torque, with low total rpm's (7-9ish roughly) and generally a 5 speed tranny. Sport bikes are generally the only place you find chain driven inline engines. These engines have much higher total RPM's (14-16kish roughly), make less torque, and often run 6 speed tranny's. Some people swear by one over the other, it comes to driving preferrence, you may not give a shit either way.
Insurance, definately check around. Also decide what sort of coverage you want. If you own a home and plan on keeping the bike in the garage except for your weekend cruise, don't bother with theft and vandalism. If you plan on commuting daily with it or live in apartments with unsecure parking areas, go ahead and step it up. I checked and got quotes with 4 or 5 different companies for a 250cc sport bike (sport bikes are generally the highest as far as motorcycles go) FULL coverage was $300 a year for a 23 year old male in Las Vegas. On a ~$3-3.5k bike. You can discounts with MSF membership ($10 a year) with most major insurers. Also many motorcyclists i have conversed with recommend Dairyland for insurance, i do know that they do not cover California though. Another incentive I'm switching to a bike is that a quote for my fully paid for car for minimum legal coverage was about $3k a year. Big difference between auto and motorcyles! Also, many companies will lower your rate a good bit after your first year of riding, some again after 5 i think.
I've been researching for a couple months now, pretty thoroughly...hopefully I'll be able to sell the car and buy the bike mid winter. If you have any questions, fire away and I'll see if I can help. Good luck
