I used to put my panos together by hand in photoshop and it would take me about 12 images without getting much sky or ground.
Then I got lazy and picked up a copy of PhotoVista and used that to automate the process for a bit but was never really happy with the control it gave me. Then one day I had to re-install and my serial number wouldn't work anymore and their tech support told me to just buy a new copy

Next I started using Pano Tools by Helmet Dersch which is a freebie but not very easy to use. Never had much luck with that until someone came up with PTgui (www.ptgui.com) which help automate the Pano Tools process.
Finally I liked the results enough that I managed to obtain a 180 degree fisheye lens for my digital so instead of having to take at least 12 photos and still leaving out the sky and ground I can now just snap 3 and get a full 360 pano like the buttercup one.
Unfortunalty Helmet Dersch got sued by the makers of a competing piece of panoramic software who claim they have the exclusive right to write software that converts 180 degree fisheye images into panoramics

But thankfully since Helmet's software is open source resourcefull folks can edit the source code themselves to re-enable this ability

So for the buttercup comp pano I shot 3 fisheye images, adjusted the colors and exposures to match (one seam is almost invisible just to the left of my rail, the other isn't as nice to the left of the group of people...the other is almost impossible to find.) ran them through a modified copy of PanoTools using PTgui and voila!
Mix in a little java to make the resulting image "interactive" and you've got a panoramic!
You can actually see the source image in unwarped form here:
http://www.hitesman.com/jason/sanddunes/pi...x3/bestpano.jpgBut you don't really want to do that since the seams are more visible that way

You can see what an older 12 image pano is like on the shot I printed out and sent to Slappy of olds from new years day 2000:
http://www.hitesman.com/jason/truck/glamis...2k/newpano1.jpgYou can also see that one in a viewer at:
http://hitesman.com/jason/truck/glamis/y2k/But the image is SO big for that one that most people can't view it. And it's got ugly top/bottom borders and since I had to take 12 shots of a busy scene there are some vehicles that appear more than once because they were moving while I was shooting. BTW - The yellow car facing away from me in the center of that shot belongs to a poster on this board...it's a turbo rotary (triple rotor IIRC) SU car...can anyone (other than the owner) name the owner

(Hint there's a side shot a little lower down on that page)