Baumgartner is attempting to set a new record for the highest skydive in history. The plan is for him to use a small capsule attached to a helium balloon to carry him up to 120,000 feet (36,576 meters), where he'll pop open the door and leap out into the very thin atmosphere. At that altitude he'll be right on the edge of space and the thin air will provide very little resistance. It is believed that he'll quickly accelerate past 690 mph (1110 km/h), breaking the sound barrier in the process. After free falling for about five minutes, he'll then pull his ripcord, and in theory make a long slow descent back to Earth.
The reason the weather needs to be just perfect for this flight is that the helium balloon that carries him aloft is very delicate and can be easily damaged by winds. In order to ensure Baumgartner's safety on the way up, his support crew is not taking any chance. The balloon has preformed flawlessly in two test runs at lower, but still substantial, altitudes but now that it is time for the big event, they aren't going to rush into anything. Considering Felix has waited years for this jump, and survived all kinds of obstacles including legal challenges, I'm sure he can manage to wait a few more days.
The jump, when it does eventually happen, will be broadcast live on the Internet. Stay tuned for updates over the weekend on RedBullStratos.com for what should be a pretty spectacular event to witness. In the meantime, check out the video from one of his test jumps below.