Nothing to it really, for 110 anyway...
Turn off the power, first off. Flip the appropriate breaker or the main if you want to be double-sure. Make sure by plugging in a light you KNOW works and is on... (plug in and then flip the breaker

)
For wall outlets, they're really easy. Take off the cover by removing the center screw. Remove the top and bottom screw holding the outlet in the box. Pull the outlet out of the box, take the wires loose from each side (should be white to one side, black to the other, and a bare copper wire ground to a green screw at the bottom) Take your new outlet and attach the wires under the screws, white on one side, black on the other, and bare to the green ground screw on the outlet end. Push it back into the box, guiding the romex wire to the back out of the way (it's pretty stiff) and then install the two mounting screws, top and bottom, replace the cover, and install the cover screw. Done.
For the switch, remove the two cover screws top and bottom, and remove the cover. Remove the top and bottom mounting screws holding the switch in the wall box. Pull the switch out of the box and you'll see two screws on one side with the wires attached. They will both either be white or black, but not both (doesn't particularly matter which-- switches are in series in one leg of the circuit that's why both the same color) It doesn't really matter which color or what anyway, because if the circuit has worked it's wired correctly. Anyway, just loosen both screws and remove the switch, attach both wires under the screws of the new switch (either one, doesn't matter, no polarity) and then push the new switch back into the box, guiding the wire to the back of the box (it's stiff wire) and then install the top and bottom screws securing it in the box, and then install the cover and replace the two holddown screws. Done.
Easier to do than it was to type. There is no "polarity" with AC voltage used in houses, and at any rate, since your not doing an installation, all you have to do is take the wires off the old component and put them back on the new one. So long as you don't switch the ground wire (bare copper) for the hot or return leg (black or white wires) there's no problem, and you're not putting a new box and switch in somewhere there hasn't been one before, so this is about as simple a job as you can do besides plugging in the toaster...
You can do this quicker than it took me to type it! Hope this helps! OL JR
