I second everyone's comments here about being as valuable an employee as possible, which generally makes your bosses more willing to accommodate you. If you think right now you're considered average or below average, I'd definitely recommend spending the next month or so really going the extra mile, then broach this conversation when everyone's feeling sunshine and roses about you.
Second, think about any ways in which your working from home could be an inconvenience to your boss or those around you, and think about ways to address those. My fiance telecommutes 3 weeks a month, and his company has a "hey, let me walk over to your desk to talk to you about this project" sort of vibe, so he actually set up a tablet on his desk at the office that he skypes into every day, so people can just go over to his desk or carry his tablet into a meeting.
FYI, my fiance did this to move to a cheaper city...the city where I live. He test-drove it by asking to work from my place for a week (which turned into two weeks due to an unexpected snowstorm), which his boss agreed to, and then made sure to be especially productive for those weeks. After returning, he raised the possibility with his boss of moving and telecommuting 100%. The boss wasn't OK with that, but agreed to a 3 week-1 week arrangement, with fiance flying back 1 week a month on his own dime (I know this sounds super anti-mustachian, but the job is in a high-salary, high-COL, high-state-income-tax location, while we now live in a low-salary, low-COL, no-state-income-tax location, so he actually comes out way ahead of either living near work or getting a comparable job here, even after the cost of the plane tickets). They both agreed this would be on a "trial" basis, and fiance was very vigilant about checking in with his boss each time he was back in town to make sure the boss was still feeling good about his work and was OK with the arrangement.
I have another friend who's in a two-day-a-week telecommuting situation. Same deal, she was a good employee and told her boss it was something she'd really like to be able to do and asked if she could do it. If you think your boss might freak out if you asked for full telecommuting, it's probably a good idea to ask to switch to a two or three day a week telecommuting plan instead, on a trial basis. If she agrees to this, I'd recommend pulling your productivity back a little on the days your in the office, and being super-extra-productive on the days that your home, just to further her impression that you working from home is a super-productive arrangement. After this has gone on successfully for awhile and everyone's gotten used to it, then you can raise the possibility of a full telecommuting schedule that would allow you to move.