OHbaby! sleep expert and baby whisperer Dorothy Waide encourages swaddling because it imitates the security of the womb. It's good to swaddle until 11 weeks of age, and then you can switch to a sleeping bag.
Dorothy has two favourite swaddles. The more traditional "Cross Your Heart", which cocoons the baby's arms against this body, and the "Snow Angel" which is great for babies who prefer to have their hands up.
Watch Dorothy's demonstrations here: