PVC tubing works well, because it is strong, light, and you can cut it into smaller sections to carry up. The problem is using the PVC couplings. They are shallow, and do not hold very well even with duct tape. I would reccommend making some support brackets out of aluminum angle. Cut them about a foot long, and use them to support the pvc couplings (2-3 per coupling) by wrapping duct tape around them and the pvc pole.
Reply To: Flag Pole Ideas Frodo