I make sure they have their choice of full sun or full shade by placing them in the sun but place a large plant (almost 3/4 the entire enclosure) inside the enclosure to provide shade and I always have water available.
Here a couple good care sheets.
http://www.bluebeastreptile.com/panthercaresheet.htm
http://www.screameleons.com/portal/a...opDefault.aspx
http://chameleonsonly.com/Chameleon%20Care.htm
http://www.flchams.com/general_chameleon_care.asp