Rewrite Rule Help ! First Time?

I need some help, It´s my first time using the Rewrite Rule for a link.

My website is a eshop.

The url will be something like this:

www.mydomain.com/shop.php

This file, shop.php will receive up to 3 parameters throught the url.

Example:

Case 1: www.mydomain.com/shop.php?page=1

Case 2: www.mydomain.com/shop.php?page=1&category=1

Case 3: www.mydomain.com/shop.php?page=1&category=1&subcategory=3

What I need is that the Rewrite Rule returns me something like:

Case 1: www.mydomain.com/shop.html/1

Case 2: www.mydomain.com/shop.html/1/FeaturesItems/

Case 3: www.mydomain.com/shop.html/1/FeaturesItems/BrandName

Let's Imagine that FeaturesItems is the Category that his Id is the number 1.

Let's Imagine that BrandName is the SubCategory that his Id is the number 3.

Can you help me to create the rewrite rule?

The other question is, in shop.php I can read the $_GET['category'] with the Id?