I went to http://good-tutorials.com and went to the flash section. There is a part that has loads of navigation tutorials too. Thats how I learned it! The navigation bit is here.
The answer is don’t. A Web site should not be made in Flash, it will only annoy and frustrate your users. Certain contents elements can use Flash very successfully, but not the whole site. Please love your site users more than that, use HTML with CSS. They will thank you.