Although it's a bit late . yes you can do it. Go to the naviagtion settings in your GPS and find the setting to change to Latitude and Longitude. You can also set how it accepts and displays the coordinates. Decimal Lat and Log or degrees minuets and seconds etc. Then go to this site Find Maps, GPS, latitude and longitude information for any location it gives you Lat and Log coordinates for any place on earth . Find your route starting point and click on the red map pointer and it gives the coordinates of that spot . Enter it as a new waypoint into GPS . Go along like that until you have all the waypoints you need and then assemble them in a route in the GPS. I guess you have already done it by now but this may help someone else.
My suggestion is don't even worry about lat/lon. Simply draw a 'Track' for the path you want to take using the imagery in Google Earth, save it as a .gpx file, then use Garmin MapSource or Basecamp to open the .gpx file and send the track to your GPS.
Yes, and I just did what Eric said also. Last week I used the GE created track in my hand held to hike a new piece of land in MT. It worked beautifully!
I'm using an app called "Earth Bridge" which links a USB GPS receiver (BU-353 and many others) to Google Earth. Google Earth dispalys latiude and longitude as well as elevation anywhere the mouse points to and it can measure distance between points in various units.
The Earth Bridge app displays the GPS postion on googles images. It optionall keep the display centered on your current location. It will also optionally auto-rotates the display orientation to the direction the GPS is moving.
I use it under XP on a 10" Acer Aspire and a 15" Dell notebook. (under $300 with the GPS for either) Neither have built in CD's keeping them light weight. The 10" display is clear with a magnifier but I have trouble with my WWII vintage eyes.
Google's satellite images and maps of an area can can be downloaded and saved in advance so an Internet link isn't needed in the field. The high resolution satellite images are great because you can easily pick out individual trees and other terrain features as distance reference points. It's slower than using a laser rangefinder but about the same accuracy to idenfiable surface features.