If you want to end up with chicken that has crisp skin all around (and who doesn't?), roasting vertically makes perfect sense, since you never need to flip the bird to get it even on all sides. Here's how to get good results, as explained by fourunder and others on Chowhound:
• To keep the bird securely upright, consider buying a vertical roasting rack, or insert a can (pictured) or the center of a tube cake pan into the main cavity.
• Consider roasting upside down by inserting the rack into the neck opening. This exposes the legs to more heat to make sure they cook all the way through, plus the fat from the legs bastes the breast as it cooks, greygarious says.
• If you roast upright at a temperature over 400 degrees Fahrenheit, set the bird in a large pan with sides at least 2 inches high, to prevent splattering. (acgold7 prefers to roast at 375 degrees Fahrenheit for 15 minutes per pound, raising the heat to 450 for the last 15 minutes.) Covering the top of the chicken with foil prevents the skin from scorching.
Discuss: Vertical Roasting - Yay or Nay