You can obtain information on the Bogen Manfrotto line of tripods, with perhaps the best value/price ratio available, at the Manfrotto web site.
B&H , a New York photo and video company, is a well established and very reliable source for tripods. Professional video equipment may be purchased at other reputable mail-order houses as well. Be sure to ask about return policies and shipping costs.
In the Seattle area you can find Manfrotto tripods and pan heads at Glazer's Camera Supply.
A good tripod and head combination for the serious videographer might be the Manfrotto 3001 or the more expensive, but more rigid Manfrotto 3040 tripod with the 3063 head and the Manfrotto 138 ball leveler. The advantage of the ball leveler, which costs under $100, is that it allows leveling the camera without having to adjust the tripod legs. Match the tripod to the camera: there is no advantage in having a huge heavy tripod for use with a small digital camera. A lighter tripod will work fine!
You can certainly shoot good video with a hand-held camera, especially if the camera has electronic or optical image stabilization. But for a rock solid image, especially for shots where you have had to utilize the full power of your zoom, a tripod is a must. And for smooth panning -- following a moving image -- a well made fluid- damped pan head is essential.