The smaller and lighter a camera is, the more likely it is to shake when you go hand-held.
Many cameras have built in image stabilisation systems, but some of the smallest and lightest don't, such as Apple's iPhone.
However, there's an app for that, or there soon will be. The Steadicam Smoothee, from Tiffen, is the smallest of the famed Steadicam camera stabilisers.
You simply clip your iPhone 3GS into a holder, fit it to a small carrying system, and you can do smooth looking camera moves, with no shakes.
It will also be available for the Flip HD, and probably for other small cameras in the future. As demonstrated by Robin Thwaites (International Director of Sales, Tiffen/Steadicam), it is quick and easy to set up, and to move. Its iPhone mount can also be used as a table-top stand or mounted on a tripod.
There's no price yet (it'll probably be in the £100+ range), or release date, but probably later this year.