[Solved] Duel booting windows 7 and a version of linux

There are hundreds, probably thousands of tutorials if you just Google this. My only advice is that you install Windows before you install Linux. But again, Google will help with this; no need for me to re-invent the wheel.

You shouldn't really notice any differences. Linux is completely capable of taking over your every day tasks relatively painlessly.

Not at all! Scripting can come in handy (Bash/Shell), but it's 100% optional.

Depending on the distribution you choose, you can download an *.iso directly from the project website. You can then burn this image to either a CD and install using that, or use a utility such as Unetbootin to create a bootable USB stick capable of installing the OS.

There isn't one! There's a lot of factors that determine which distribution is more or less suitable for a given person, which is the reason there's thousands of distributions. I generally suggest Mint (www.linuxmint.com) or Fedora (www.fedoraproject.org) for beginners, but you may want to use something else. www.distrowatch.org has a great list of distributions by popularity.

Good luck!