Since I get a lot of mails from people who do not seem to be able to install the mod, i thought I'd make a fool-proof tutorial. You need to have WinRAR installed to do this. Here goes.
STEP 1: Download all parts of the MOD. You can right click them and select 'save target as', or left click them, which has the same effect. When you see the screen below, click SAVE and put the files in the same directory. This means all the files. This does not have to be the directory where GTA3 is installed, it can be any directory, as long as they're all together. By the way, a 'directory' is the same as a 'folder'.
STEP 2: Here you can see all the files in the same directory. They should all be the same size, except for the last one, which will almost always be smaller, never bigger. Doubleclick the first file, i.e. the one that's called kipsmod.part01.rar
STEP 3: (still with me? Good.) After you doubleclicked the file, you should see this on your screen. This is winRAR. Click the 'Extract to' button to extract the files.
STEP 4: Now here's a tricky bit: you need to select a folder or directory if you will to extract the files to. It does not matter where you put it, as long as you can find it again later.
STEP 5: Click the 'OK' button to start extracting the files. This is what you'll see. When it's done, you can safely close winRAR.
STEP 6: Open the readme file and READ IT. It can contain vital information for your survival.
STEP 7: Now, doubleclick the .exe file you just extracted. It should be in the folder you selected earlier. You'll see this window.
STEP 8: Select the folder where your GTA3 is located. You can do this by clicking the button with the three dots, and browsing to your folder. Click 'Install >' and WAIT until you see the window displayed below. Then click 'OK'.
Now, if you've still got problems related to corrupted .rar files, try downloading them again, starting with the ones that are not identical in size. If the files are OK and it still doesn't work, go see a doctor. You might be seriously ill. I've actually seen 10 year old kids do this without reading a manual. Go figure.