Oh no! It's horribly, horribly cold outside. Not to mention windy and raining and I had wanted to grill some yummy hamburgers. Never to fear as this is more or less the exact reason why you have a broil setting on your oven.
What is broiling?
Essentially broiling is cooking directly under the heat. This differs from the 'bake' setting rather significantly as baking fills the oven with indirect heat. Hence the reason why the oven needs to stay closed while baking and also the reason baking takes longer. As such broiling is often used on thinner cuts of meat that will be cooked quickly. Those used to grilling (or, as some people who have yet to learn to importance of slowly smoked meat sometimes erroneously refer to it "barbecuing") will likely understand this as the difference between direct grilling over hot coals (such as for hamburgers or sausages) and indirect grilling over a drip pan (as one would do for a whole chicken or such). Broiling can also be used briefly to brown or crisp foods, melt cheese or any other task where a direct heat source would be helpful.
In practice broiling is very quick and simple and a great way to prepare meals. In a pinch it can also be used to cook most foods that you would traditionally grill over direct heat (e.g. hamburgers, steak, boneless chicken breasts) when that would not be practical or convenient.
Most ovens will have 'broil' as a setting on the oven and will accomplish the broiling in the same oven enclosure. Some, typically gas ovens, have a separate, smaller area reserved for broiling.
How to broil
The first thing you'll need is a broiler pan. These are largish pans with two parts: a thin top section with many small slits and a deep bottom section. The food rests on the top portion while the bottom acts a drip pan, hence the slits. This prevents the food from cooking in its own juices. Not that that's a bad thing, but it's not what we're interested in doing. When not in use for broiling the bottom pan can be used for roasting and baking.
First move the rack in your oven to the top-most setting and place the broiler pan on top of it. Adjust the rack height until the top of your pan is at the correct distance as specified by your recipe. In general you want a distance of about 3-4 inches away from the top for cuts of meat up to 1 1/2 inches thick and 4-5 inches for thicker cuts. If you're using a gas oven you likely won't have much say in this matter. There may be a few slots that a broiler pan will fit into or you might just not have any options. Try to do your best and, if necessary, simply adjust cooking times as needed.
After adjusting the rack remove the pan (a note on technique: I have heard that a broiler pan should remain in the oven to heat up, just as a grill will heat. I, however, have not heard this stated as a universal and personally do not pre-heat my broiler pan). Set your oven temperature to 'broil' and pre-heating for a few minutes. Unlike with most pre-heating we're not trying to fill the oven with heat, what we want is to have our heating elements reaching their maximum heat. Anything more than 5 minutes or so and you're just wasting your time. While this is going on we will prepare the pan.
If you are using a non-stick pan you can ignore this, otherwise cover both sections of the broiler pan with aluminum foil and use a knife to slice through the slits. This is not strictly necessary, but it will make cleaning much simpler. Either way remember to lightly oil the pan with either a bit of non-stick spray or a very brief rub with some oil. Just like with your grill grate you only want a very, very light coat that will keep food from sticking. The heat will do all the cooking, not the oil.
Now that you have your pan ready and your oven heated place the food you wish to broil on top of your broiler pan. As stated above the best foods to broil are thin and do not require a great deal of cooking time.
At this point things get a bit different depending on whether you have a gas or electric oven and if it features a separate broiler compartment or not. As always consult your manufacturer's instructions to be certain.
When using an electric oven slide the pan into the oven, but DO NOT close it. Well, that's not entirely correct. You want to close it, but not all the way. Ever wondered why your oven has a stop that will allow it to stay open a few inches? This is why. Set your oven to this slightly ajar point and start your timer. A gas oven is pretty much exactly the same, but you will typically keep the door closed instead.
Do not leave the food. Broiling takes very little time and if you leave the food for even a short amount of time you will likely return to find it charred and burned.
For cooking times consult your recipe. Most grilling times will remain more or less the same. As well you can consult a cookbook with a good general reference section such as that old standby, The Better Homes and Gardens Cookbook or The Joy of Cooking. Technique should be the same as grilling: don't pierce the meat while cooking, turn only once, etc.
If merely using the broil setting to brown or crisp something simply switching the broil setting on for a minute or two at the end of the cooking period is often sufficient. Do remember to set the oven door ajar if using an electric range however.
Hopefully you now have a much better idea about what that mysterious setting on your oven is used for and a newfound desire to start broiling some delicious food. As with all new cooking techniques don't be discouraged if your first few attempts are less than satisfactory. Try to approach them as learning experiences and adjust accordingly. Soon you'll be preparing quick, wonderful meals and delicious grilled dishes regardless of the weather.