Some of you with kids have this problem too. You might have a perfectly nice sofa but it already has a TON of stains. Cleaning the fabric is just out of the question. Or perhaps you have a dated couch. You want a sofa makeover.
I've read magazines and seen home makeover shows that tell you to go to someone who can make one for you but honestly, for the cost it would take to do that you might as well buy a new sofa.
Here's a great slipcover tutorial from pink and polka dot. Use this chart to determine how much fabric you need to buy.
Take it from someone who has made her share of slipcovers over the years, it's doable.
Just take my advice. Don't sew a whole slipcover in white and have to make a new one two months down the road because you have messy kids. Make your fabric decision carefully. It's doable but daunting.