I am changing the structure of my website and putting most of my pages into sub folders. My question is this, do I need an index.html file for each folder ? I want my page to look like this http://www.sandisk.com/Products/ how can I achieve this? what is the reference page
I would say yes. If you put files in a folder and no index file if someone happens to type in that address they will see an index of your files and your files could be stolen at that point. Just my opinion.
when making links to reference my page, will it be http://sandisk.com/products or h ttp://sandisk.com/products/index.html ?
You can use either one as the browser will automatically seek out an index.html or index.php file when is goes to yourdomain.com/products/. But if you have a directory without a index file it will show all your files and you can get them stolen that way. I hope this helps,