Great starting point for camera and lens data to find your no-parallax point.
Link to a Nadir technique tutorial by Hans Nyberg. Hans is a panorama guru from Denmark and his technique does not require to take the camera off the pano head.
A YouTube video from 360Cities.net that shows the first basic steps how to shoot the photos for a 360 degree panorama or photo-sphere with a SLR camera and a fish eye lens.
A must read tutorial if you need to find the no-parallax point for your camera/lens equipment. John Houghton is a UK based panorama guru who has compiled excellent tutorials.
Smooth's method for finding the correct lower and upper arm positions of your panorama head is easy to follow and provides repeatable good results.
Another great tutorial from John Houghton on how to mask out areas with an alpha channel.
This tutorial provides instructions how to eliminate yourself, others or your tripod from the final panorama.
Rosauro has a good tutorial about one of the many techniques to take Nadir shots for panorama photographers who do not want to cheat with a Nadir cap.
The Guide to Panoramic Photography is a great site by Arnaud Frich with tutorials on photographing, stitching, building of tours etc.