Check out these sites, they will help you out immensely:

http://www.sheldonbrown.com/fixed-conversion.html
http://www.sheldonbrown.com/singlespeed.html

You can still use your wheels. If its an older road bike it might have a cassette freewheel, meaning you can unthread the freewheel and throw on a fixed gear cog. This is considered a suicide hub. People will tell you its stupid to use this method, but alittle loctite or jb weld will keep things secure. However, if you plan on riding brakeless, get a new rear wheel. Check out this site on how to rotafix the fixed gear cog onto the hub if you plan on using your existing wheels. Oh yeah, if you do use your current wheels you will need to redish your wheel, thats covered in the sheldon brown articles.

http://204.73.203.34/fisso/eng/schpignone.htm

For the price of bulletproof cranks I would suggest looking at ebay for a set of older Shimano 105 or 600(Ultegra) cranks. Make sure you get 165mm or 170mm as anything longer you will run the risk of clipping your pedals through a turn! As for bottom bracket you need a 68x107, plenty of brands carry this size. Shimano has the UN-54 which is under 20, but I hear you cant take it apart. I personally run a Tange Seiko bottom bracket which is by far one of the smoothest bottom brackets Ive owned.

As for gear ratios, I would suggest an easy ratio like 44/16 or 42/16, it will help you get used to spinning. As you gain strength, put on a larger chainring or a smaller cog.

If you have any questions, post em up!