Sorry for slow reply, been a bit busy at work lately.

RobertN laid it out pretty well. They are regular soda kegs, can sometimes be creatively scrounged, bought pretty cheap from homebrew suppliers, or you can actually buy really nice new ones from places like Williams Brewing. You will need a CO2 tank and regulator; many homebrew suppliers can supply the regulator, the tank can usually be leased really cheap from welding suppliers or anyplace that fills fire extinguishers. A 20-lb CO2 tank will last a long time. You can also get manifolds to split the gas supply into several lines, handy for maintaining pressure on several tanks. The taps are similar to the "picnic taps" used on regular beer kegs, although you can get all fancy and get real bar-type taps to mount on the door of your fridge (I haven't done this).

One really nice think about using kegs is that you can force-carbonate the beer rather than priming. You put the finished beer in the keg, chill it, then put extra gas pressure on the keg for a certain length of time (I don't have the figures in front of me, but I can get them if you're interested). This forces the CO2 into the beer for carbonation, instead of using a priming method to carbonate after fermentation. It's easy and relatively quick, and there is VERY little sludge (dead yeast) in the keg. I strongly recommend kegging, it's really not that expensive, and it beats the heck out of dealing with all those bottles.

There is a lot of homebrewing info on the web. Anyone that is at all serious about it should join the American Homebrewers Association and get their quarterly Zymurgy. American Homebrewers Association

Darel