Tips for long distance running?

Start with couch 2 5k to build your running base - it's about an 8-9 week programme and has you running for 30 mins/5k 3x a week by the end. Then there are tons of free marathon training programmes on the internet which rely on that sort of endurance base. You're probably looking at 6-8 months of training, so now is a great time to start as it'll give you time to have injury/family/illness/rest weeks as you go.

Maybe pick a shorter race or two as interim targets - 5k/10/half marathon to keep yourself motivated?

@Kellster111- I did find a C25K program, thanks What is Runner's World?

Runners world is a running magazine in the UK but you can get info from their website.

•Don't skimp on gear. Splurge on good wicking socks to prevent blisters, a durable and comfortable pair of sneaks, wicking clothes that are seamless to prevent irritation and chaffing, and a supportive sports bra. Good gear is so worth the extra dough.
•Follow the 10 percent rule. The rule states: never increase your weekly mileage by more than 10 percent from the previous week. This means you want to gradually work up to that 18-mile run you have in your training schedule, rather than jumping right into it.
•Slow down your pace. You may be used to running eight-minute miles when you run the three-mile loop in your neighborhood, but it'll be hard to keep up that pace when taking on a 10-mile run. As your body gets used to the increase in mileage, you can gradually begin to increase your speed.
•Don't be afraid to take walking breaks. Longer distances mean you're on your feet for longer periods of time, so you'll notice your muscles becoming fatigued. Continuing to run with a tired body can lead to muscle damage or another injury. Allow your body time to build up endurance and have some time to recover by including short walking breaks at regular intervals.

Keep reading for more helpful tips on running long distances.
•Stay hydrated. During your run, sip eight ounces of fluid every 20 minutes. Plain water is fine if you're running an hour or less. If your run is longer, you'll need to replenish lost electrolytes, so drink Smartwater or make your own sports drink with Nuun tablets.
•Consume quick carbs every hour. Aim for 30 to 60 grams of carbs every 60 minutes. Gu or Luna Sport Moons are great options.
•Figure out what motivates you to keep going. When your mind begins to think about nothing but stopping, you'll need a way to inspire your legs to keep on moving. Running outside in a gorgeous setting, listening to a new CD, tracking your run with a heart rate monitor or iPhone app, or running with a buddy may give you the push you need to reach your goal.
•Reward your efforts. Once you reach your goal, honor your efforts with a massage, pedicure, haircut, a new CD or running shorts, a sweet treat (something reasonable that won't undo all the good you did), or a night out with your favorite people. It may help to have the reward in mind before beginning your long run, so it can motivate you to keep on going.

I think it's awesome that you want to run Boston, but keep in mind you have to qualify for it. That means you'll have to run another marathon first, and beat a specified time based on your age and gender. Before the cutoff date in September. Going from zero-to-marathon in a year would be hard enough, but going from zero-to-Boston-qualifying-time-in-a-marathon in 5 months is not a reasonable goal for most people.

If I were you, I would consider volunteering for the 2014 race instead, and think of running it a few years down the line.

An article on qualifying for 2014 here: http://communities.washingtontimes.com/neighborhood/life-lisa/2013/apr/21/participate-2014-boston-marathon-start-training-no/

Best of luck!