I'm writing this Instructable merely as additional content. We all have our different ways of growing plants, and this was the best way I found to do it. I'm going to start another plant very soon, so I'll be back to upload more photos. I just didn't know about the wonderfulness that is Instructables when I started ;) Kudos to woofboy111 for his Instructable too ;) I'm going to have to try your way of doing it!
Step 1: Picking the Right Fruit
When you select your pineapple, ensure that the crown has nice green leaves already growing in the centre.
Step 2: Twist the Crown Off
Taking hold of the pineapple, twist the crown (the green part) off in a circular motion. My pineapple already had some roots growing when I purchased it, as I discovered when I removed the crown.
Step 3: Remove Leaves
Take some of the bottom leaves off; you'll want around an inch of uncovered stem. If you need to, wear gloves. The leaves are pretty prickly...
Step 4: Put the Crown in Water
Put the crown in water so that the inch of stem is submerged. Don't put too much water in the container you're using; you want to avoid the leaves rotting. And change the water often!!! Water can become anaerobic very quickly, so you'll find you'll need to change the water every 2-3 days. Don't let the crowns' base get slimy. If it does, very gently rinse it, clean out the container thoroughly, and refill. But if you don't change the water regularly, you'll have a rotten crown in no time.
Step 5: Wait Until Roots Form
You'll need to wait until the incipient roots are around 4 inches long before you transplant.
Step 6: Transplant Your New Plant!
When it comes to transplanting, find a pot with good drainage, and use a good potting mix (I've used some left over cactus potting mix this time around). Don't overwater the pot, the new roots will rot. Pop it in a sunny spot, and only water when the soil is dry. That's it!! Once the plant has outgrown it's first pot, you can either move it up to a larger pot, or transplant into the ground. And in three years, free pineapples!!!