Very very easy. You don't need fancy skills or a special sewing machine, just the basics.
Have a look around online for a pattern, or make your own and experiment a bit to begin with - use some cheap, recycled material till you get the hang of it and find a pattern/style that suits your baby.
I've been making pockets recently and I'm quite chuffed with myself Including the absorbant booster bits that go inside they're less than $10 each.