Here I go native when dual booting. When I install another OS the boot manager is automagically installed and I get a boot menu. I can't guess how you installed and didn't get a boot menu.
There is a free boot editor system at http://neosmart.net/EasyBCD/ that I've used but for many reasons I never support dual or more boot machines. They tend to break too often and folk refuse to backup when it does work so to fix them is way too many hours which runs up quite the bill.