Thanks for all the good advice! Unfortunately I already have the upper canyon booked and won't have time to do the lower. I wish I had several days in this area.
that was my problem as well.. at the time, i hadn't seen much difference between upper and lower except for the sunbeams, so i chose the upper (i got one during that tour that's been my best selling image so far, and has earned me enough to pay for the entire 10-day road trip!), but if i were doing it again, i'd spend an extra day in Page and do the lower canyon as well.
while you're there, if you have time, drive 2 miles south of Page on hwy 89 and look for the sign for Horseshoe Bend... it's about a half-mile hike, maybe a bit less, from the parking area to the canyon rim, and it is definitely NOT for those with a fear of heights (it's about 1100 feet straight down to the river and there are no guard rails!), but the view of the canyon is absolutely stunning! with a 10-22 you should be able to get it all in one shot - i couldn't fit it all in with a 17mm on my 40D, so i had to shoot several frames and stitch... try to get there either between 10 AM and 2 PM if you want the canyon lit, or go at sunset... either one will be a splendid view!