In Reply To #1 I don't think that would be good for a couple reasons... Pouring over ice might have bad effects on the beer because of the instant temperature shock. Also, it sounds like it would be a risk of contamination. I always make sure the water I add is clean. Ice has been open to the air and freezer for hours.
In Reply To #1 If you are not doing a full wort boil, you can boil 3 gallons and then add 2 gallons worth of ice to top it off and cool it. Be forewarned though; ice can be full of contaminates. Any bacteria that is in the water when it is frozen will stay frozen, and thaw out back to life. The only way to kill these is to boil, or hope that the yeast will over power them. I suggest you use bottled spring water and keep it near freezing in the fridge, then add that to the partial boil. That will cool things down almost as well as ice, and you can be fairly certain there are not contaminates in the water. Another idea is to boil 2 gallons ahead of times, then put it in an airtight bottle and refrigerate that. An ice bath works, but it's too slow IMO. Getting the wort to pitching temp as fast as possible is imperative. I suspect you are in fact doing a partial boil, but if you are doing a full wort boil, I strongly recomend investing in a wort chiller. They can be a little pricey, but are very easy to make with a 3/8" copper tubing from home depot. I hope this helps?
For Cottrell: I'm a novice brewer, and as such haven't obtained all the bells and whistles yet. For a wort cooler, you mentioned copper tubing. Is this just a coil of tubing with a fitting for your water source, and do you sanitize it along with the rest of the equipment?
In Reply To #5 A wort chiller is just a coiled piece of copper that has plastic hoses attached to it. At the end of one of the tubes is a fitting for your garden hose, but you can adapt it to fit your kitchen sink if you feel the need. The wort chiller goes into your pot with 15 minutes left in your boil. Because it is put directly into your boil, there is no need for santizing it. The boiling water will kill anything hitching a ride on it. There is also a different copper chiller which is a called a counter flow chiller. These work like this: your wort travels through a copper coil, and an adjacent copper coil is carrying cold water. This cools your wort much faster than the normal chillers. The thing that scares me about this is the wort is traveling through a small copper coil. I don't like the idea of having wort traveling through there, with all kinds of possible contaminates. Also, I've heard stories of these becoming clogged with hop leaves and such. This is something I will look into if I ever upgrade my equipment to doing 10 gallon batches, but for now, I'll stick with my regular cooler.
In Reply To #7 There's nothing wrong with making your own wort chiller. You'll need 25 feet or so of 3/8" copper tubing, and some 3/8" vinyl tubing. Just be very careful not to crimp the tubing or you'll become a very angry homebrewer. Let us know how it goes if you decide to make one.