Photoshop preloading?

Erm im kinda stuck. I dont want anything fancy, but i have my site up now ( and im gonna make a splash for it, I want a preloader that starts automatically when you go to the splash page and opens the main site automatically when the preloading is over, and obviusly the site is all loaded and running smooth when it ocmes up. Is there some kind of code i can use for this or do I have to make one in flash?