Daisy,
We were on the Panama Canal itinerary Oct 17-27 2003. We rarely do shore excursions (this was our 9th cruise),but decided to do the full day excursion that included tha Rain Forest Arial Tram as well as the canal cruise. The tram was very interesting, with 5 passengers and a very knowledgable guide in each tram. Because of time of day, you don't (or at least we didn't) see much wildlife, but the amazing fauna as you pass through the different levels made it very interesting. If we saw little wildlife during the tram through the rain forest, the boat trip through the canals MORE than made up for it! We saw sloths, alligators, howler and spider monkeys, Pink spoonbills feeding at the waters edge, and untold exotic (at least looking!) birds. The excursion when we were on it included lunch at a nice open air restaurant in between the two halves. When we took the excursion, the passengers were divided into 2 groups, with one doing the Rain forest first, and then the canals after lunch. If you book this excursion, try and get into the group that does the rain forest first, since I beleive that we had many more wildlife sightings than the group that did the reverse. All in all, a very long day, and not an inexpensive excursion, but WELL worth it! Enjoy your cruise!