I used to ride (a bike) to work several days a week; it was great. I eventually ended up buying a set of street tires for my mountain bike - which made commuting much easier.
Make sure you get a helmet. I also recommend gloves. And a flashing light. I took a header in traffic one time and proved the helmet worked, but didn't have gloves. I was still pulling gravel out of my palms the next day.
I also recommend a camelbak - much easier to use than the old water bottle.
- re: falling on skateboards; When I was 13 my dad tried my old (skinny 70's) board while I was playing stickball with some other kids in the street. At one point, I saw my dad sitting in the middle of the street about half a block away. I called out asking what he was doing. He replied, "I broke my foot. Please ask your mother to bring the car down."
I said to my friends, 'Yah, right.' and we continued to play.
About half an hour later, I noticed my dad was still sitting in the street.
Turns out he really had broken his foot...
I've had my share of spills and visits to the ER for board-related injuries. I still think that if you're young enough to be considering buying a board - you should. They're fun.