Yes, Linux can boot Windows. Most distros will show you a menu at boot with the different OSs installed in your system, so you can boot Windows. You just have to make sure to install Grub (or Lilo, in case you're using a distro that comes with it) in the MBR. (Generally, you're asked where to install the bootloader when you install Linux).
As usual, it's a good idea to back up your data before installing Linux or any other OS.