I got a hot `water` smoker from the states a couple of years ago - A Brinkman. it's like a kettle drum with sections for the charcoal, and water above. this gives a nice moist cook and really works well with meat that can dry out a bit (e.g. chicken). Best bit is you can fill up the water container with different liquids and it gives a different taste. Nothing like beer flavored hot smoked ribs!!
I've smoked a whole chicken before, as well as salmon. Fish took only about 1 hour, the chicken the best part of 4-5 (was about 1.2 - 1.5kg in weight). A really good tip is to get a good meat thermometer to check if the item is actually cooked properly.
Hot smoking is where you actually cook the meat over a long period of time, in the presence of smoke for added flavour. Hot smoked sausages are really good -as well as things like duck brest, chicken. Even turkey, if you've got a big enough smoker - imagine hot smoked turkey for christmas!
Cold smoking is only using the smoke as a preservative agent, the smoke is only about 20-25 degree's. You can cold-smoke anything, but any pork items need to be cooked afterwords before eating - e.g. you can smoke a bacon joint but you'll have to cook it afterwords.
As for tips, the main ones are :
Don't open the door every 20 mins to take a look - it loweres the temperature too much and increases the time taken to cook the food
Get some nice flavor'd wood to smoke with. You are better using sawdust in a cold smoker, but you an also use water-soaked wood chips (waitrose and sainsbury's sell chipped jack daniels barrell's).
Cold smoking you're looking for a long, slow burn. I've seen on the internet metal boxes with sort of channels that you fill up with sawdust, light one end and hopefully it smoulders for hours without needing anything else.