How would you create a lesson around a virtual field trip?

The Butterfly Conservatory: American Museum of Natural History

Zoos Online: Animal Encounters

Lewis & Clark Expedition

Tenement Museum: From Ellis Island to Orchard Street

What is the value of going on a virtual field trip?
How would you plan the lesson? What would students be asked to do?

How would you connect the virtual field trip to the 
Connecticut Science Standards?