Nice page! For some reason, the Chacaltaya page was taken down several months ago. Good to see it is back up.
I wanted to add - there is a cheaper alternative than taxi - it is possible to take buses from LaPaz. In February 2010, for 40 bolivianos, a bus picked me up from Loki Hostel and drove us to Chacaltaya and Valle de la Luna. An English speaking guide accompanied us.
Thank you, the info is now at the page in the "getting there" part.
If you drive there, you go up to El Alto from La Paz. Once there, you just head straight toward the mountain. Almost impossible to get lost.
Thanks for adding this page- I considered doing this myself.