The best way to view Glen Canyon Dam is from the overlook about a mile downstream from the dam. The walk from the parking lot to the White House overlook is interesting,too, with layered upthrust red rock and chain assisted path. You also get a good view of the canyon and the Colorado River below the dam from the rim you are on.
If you go:
This is a free attraction. It only takes about 20 minutes to make the round trip hike out to the rim and back.
Links:

669 Scenic View Road
Page, Arizona 86020 USA