Thanks to the Internet, most companies are now making their software available as downloads, rather than as something that you install from a CD or DVD. That’s the case with iTunes.
When you buy an iPod, iPhone, or iPad these days, you won’t find an iTunes installation CD in the box. Instead, you'll need to download iTunes from Apple's website in order to use it -- and to use your iPod or iPhone.
You’ll need to give Apple your email address, but otherwise, it’s free to download iTunes.
Download Latest Version of iTunes
To download the most up to date iTunes for Mac or PC, go here: http://www.apple.com/itunes/download/
iTunes for Windows 64-bit
The standard iTunes program doesn't run on 64-bit versions of Windows. If you're running Windows 64-bit and want to use iTunes, you'll need to download a special version. Find out what versions of iTunes are 64-bit enabled and what OSes they work with, as well as where to download them here.
iTunes for Linux
Apple doesn't make a version of iTunes specifically for Linux, but that doesn't mean that Linux users can't run iTunes. It just takes a little more work. Check out this article to learn what you need to do to run iTunes on Linux.
Old Versions of iTunes
If, for whatever reason, you need a version of iTunes that's not the latest (and you've still got a computer that can run, say, iTunes 3), your task isn't entirely easy. Apple doesn't provide downloads of very old versions of iTunes (though you can usually find the last 3 or 4 versions if you poke around its site enough).
Lucky for you, there are sites that archive and let you download nearly every version of iTunes ever release. So, if you're looking for iTunes 6 for Windows 2000 or iTunes 7.4 for Mac try these sites:
After you download iTunes, here are some common tasks you may want to do: