Here's some light reading:

http://www.active.com/cycling/Articl...ntain-Bike.htm

http://en.wikipedia.org/wiki/Bicycle_pedal

If you want my advice: Buy some entry level Shimano ROAD shoes and some the entry level Shimano pedals I mentioned before and let that be the starting point for you. Everyone has preferences which differ here and there, but we all had to start somewhere. I used to say start with Time ATACs and a MTB shoe, but I have since changed my mind as most people actually ride more than they walk around so, take a bag with some sneakers if you plan on walking a lot at your destination (work, school, shopping). It's perfectly fine to walk small trips in road shoes let's say to the coffee shop, the bar (if you aren't walking all over the darn place), or a friend's house.

The benefit of having road specific gear as you ride your bike outweigh the minor inconvenience of *occasionally* carrying a spare pair of shoes.