Use the following two thumb rules. They work for any DSLR\SLR and the angle covered by your shots doesn't matter, it works for 0 - 360 degrees.
1. Use the mid range of your lens. If you're using a 28-80mm lens, shoot your panorama at a focal length between 45 - 60. If you're using a 18-200mm lens, shoot your panorama at a focal length between 35 - 170.
When shooting in the lens mid range, you avoid those barrel and pinch distortions that are recorded on the edges of the photograph when shooting in the highest and lowest range values.
2. Measure the exposure of the most important part of your panorama with your auto exposure meter and then set the same reading values (Tv and Av) in your Manual Exposure.
This will give you the same exposure across your entire panorama image.
in addition don't forget to use a tripod, that always helps.
Additional information can be found here:
http://www.panoramas.dk/
and if you read Hebrew you can get a good starter information here:
http://www.ynet.co.il/articles/0,7340,L-3334272,00.html