When going there is impossible
or
 you want to add to the trip before or after the visit. 

TRAMLINE on-line field trips
Includes study materials for each trip.  List includes Antarctica, Aquifers, Baking Bread, Deserts, Dinosaurs, Endangered Species, Fierce Creatures, Getting Green, Hurricanes, insects, natural Wonders, Oceans, Rainforest, American Presidency, the Big Apple, Lewis and Clark, Poet's Pantry, Shakespeare, Women's History  For all grades.

Virtual Field Trips
On-line field trips includes study materials for each trip. The site is primarily contributions by teachers of what they've studied in class.  Interesting, on‑line, curriculum including pictures in the following subject areas: ATE/Applied Technology, Fine Arts, Foreign Language, Health/PE, Language Arts, Math, Library Media, Science, Social Studies, Special Ed, Technology, Other, Online Tutorials, Professional Development.  Hosted by the Utah Educators Association

Best Virtual Field Trips 
This site is great!  It is by a California LDS HS family, and has what I would consider on-line field trips.  Many pictures or video clips with explanation. Others  are little more than annotated postcards and very useful in your studies.   I actually felt like I was viewing a tour of some of the museums and popular sites. Be careful in the Factory Tours section - there are several closed links and advertisements.  Tours of Buildings, Nature and Science, Regional Tours, Factory Tours, Educational Web Cams, Time Travel Trips.

Volcano World Virtual Field Trips
A great site with spectacular pictures and wonderful, but brief, explanations. A must do before any family goes to Mt. St. Helens! 

Scholastic for Teachers
Each field trip provides quick suggestions for using targeted Web sites for teaching a specific topic. Within each area, you'll find field trips in an alphabetical list of topics.  Has what I classify as virtual field trips, primarily, under the Science, History/Social Studies tabs at the top of this page.  The rest is samples of curriculum and visits to school sites which might be helpful to Unit Studies homeschoolers or to individuals looking to enhance their curriculum 

Virtual Worlds and Fieldtrips
Good site, similar to number Best Virtual Field Trips above.  Some of these are virtual reality sites, many are little more than annotated postcards.  Has many UK sites.

Virtual Guidebooks, Puget Sound
Some video panoramas of several historical sites in Puget Sound area.  No sound or written history included on this site but some great views of Fort Nisqually, Union Station, Tacoma Waterfront, Seattle, Mt. Rainer, and much more.  You can visit your field trip sites on-line first and then go on your trip.  You can find other guidebooks there too.

Spawning Salmon on the Skagit
Video clip

Burke Museum Virtual Tour 

Ballard Locks or here or here

other Washington State attractions