There have been several questions and requests here regarding dual-booting. While there are many explanations on the web on how to do this, I have not found any that were fully clear and complete, so I created my own, which are attached here.
If you use these, and find any problems (something not clear enough, screen didn't come up as stated, typo's, whatever), please PM or email me so I can correct it (and let me know which one you were using!).
By the way, if you only wish to install one OS, these instructions should work for you as well, just use the part for your particular OS.