Linux will give you its own bootloader for doing both linux and windows.
The best way to do it if you're not sure you even want linux though, is installing Lilo on a floppy. It'll ask you to do a bootdisk for fixing problems, and that's ok but it takes forever for linux to boot up that way. When it asks you were to install Lilo it'll probably say something like hda0 but instead pick fd0 or whichever is the floppy drive. That way if you don't end up wanting linux you could just toss out the floppy and aside from the disk space taken up in another partition, your computer won't know that it even has linux on there.