Now that you have the games, you are almost ready to ruin them by not properly preparing yourself. Doing a few fast and simple tweaks can really mean the difference between loving these games or walking away in frustration after your first character can't finish some quest in the main storyline.
First, install your games. If you have the discs, I recommend the humongous installation (try not to laugh, 600 megs was a lot of disc space back then) because you don't need the disc in your drive if you use that option. You can alt+f4 to skip the previews of ancient games that the installer plays after finishing. Or watch them, you might want to pick up some of the other classics if you like the old Fallout games.
Next, download and install your patches. Fallout is generally playable without them but you won't like having to start your game over in the last city because you ran into one of the release version's major bugs. These links provided assume you have the retail US version. Otherwise, please search these sites for the downloads needed for the version that you have.
Fallout 1
Official 1.1 Patch
Download and install from Interplay:
http://www.interplay.com/support/support.php?id=119
or from No Mutants Allowed:
http://www.nma-fallout.com/forum/dload.php?action=file&file_id=48
Unofficial 1.34 TeamX Patch*
from NMA:
http://www.nma-fallout.com/forum/dload.php?action=file&file_id=1075
Fallout 2
Official 1.02 Patch
From Interplay:
http://www.nma-fallout.com/forum/dload.php?action=file&file_id=1075
From NMA:
http://www.nma-fallout.com/forum/dload.php?action=file&file_id=1075
Unofficial 1.02.25 Killapp Patch*
from NMA:
http://www.nma-fallout.com/forum/dload.php?action=file&file_id=1075
Next, if you bought the disc version and are like me, those annoying registration screens simply must be dealt with. To do so, you need to manually edit a text file on each game. The steps are identical for both games other than the install directories.
Open the file (install directory)\EREG\EregUI
Hit ctrl+f
Type "run=" (without the quotes) into the find window
Close the find window
Change the text "Yes" to "No"
Hit ctrl+s
Close the text editor.
After all this, I recommend reading the manual. I realize nobody will do this because reading a manual sounds about as fun as bathing in a tub full of scissors but its actually entertaining. At least flip through the PDF manual on your disc and admire the doodling.
*RAR files are an archive file like ZIP files, they are used because they are more secure and tend to compress at higher rates. If you need an application to unzip RAR file, I highly recommend 7zip because it is compatible with every archive format in common use on the internet from zip to tar, you can get it at http://www.7-zip.org/. After downloading it, you can right-click on the RAR file and use the 7zip context menu to extract the files.