Karen and I built an immersion chiller to speed up our brewing. You can easily make one of these for your homebrewing. All you need is 25 to 50 feet of copper tubing. The 1/4 inch diameter tubing is cheapest and will work well. You will need two adapters to convert the 1/4 tubing to garden hose. HomeDepot has all these parts. You can get it all for about 20 to 30 bucks.
The chiller will shorten brewing time greatly. With all malt or partial malt recipes, the chiller will reduce the cooling time required prior to pitching your yeast to 15 minutes or less.
To use the chiller, you connect your garden hose to one of the inlets on the chiller. You connect another hose to the outlet. This second hose is just to direct the waste water away from you and the beer so any hose should work. (I have heard some people connect the hose to a sprinkler to water their yard at the same time.) After connecting everything together, you place the chiller in your brew pot and turn on the water.
It should be noted that the chiller should be cleaned just as all brewing equipment must be sanitized prior to usage. If your brewing method includes boiling the malt, you can sanitize the chiller by placing it directly into the brew pot during the boil to sanitize the chiller.