NOTE : We've moved this discussion from the thread at http://chowhound.chow.com/topics/8206... -- THE CHOWHOUND TEAM)
Hot smoking cooks the fish. Cold smoking smokes cured fish at a low temperature.
Hot smoked fish is cooked fish but via a method that produces smoke. Think smoked barbecue, but not as much smoke. I generally use a stovetop smoker, and alder sawdust, to do this as you get a nice smokey flavor and the fish essentially poaches in its own juices. Delicious.
The majority of smoked salmon is cold or "low" smoked. This is the traditional method. The temperature stays below about 80 degrees. Any more and it cooks. It smokes for a long time so the fish needs to be cured before the smoking, usually with salt. So cold smoking does not cook the fish, it is cured and then smoked.
There are many resources for cold smoking on the web. Recipes and techniques vary by culture and chef. Its hard to do right without experience and frankly a proper smokehouse designed for cold smoking. Thats why I buy it instead of doing it myself.