It's not the diskspace and bandwidth what should worry you that much gantlet, first need to install apache on your machine, then you will have to worry about the security, then about the electricity bills etc..
Anyway, you can find like tons of tutorials about installing a server at your own machine all you have to do is search in google or any other search engine and read the tutorials carefully, once you get errors or get stuck somewhere you can bring the topic here again, i belive someone if it has some free time will gladly help you.
I am currently hosting my website at home and it is a real pain. It was fun to setup and make it happen but you will need a separate computer with either windows server or apache. Then you will need to make sure you have a static ip so people can find you on the internet or you will have to use a service to do it. There is also alot of security, people with servers get hacked. I would suggest if you do it, do get a hardware firewall. I use a netscreen firewall, I hope this helps. Currently I am in the process of finding a host to put my site on there, as I am tired of dealing with it at home.