I don’t think there’s an easier way to geotag your digital photos in Windows. Check out the free Panorado Flyer:
JPEG image files can contain supplementary information (so-called Metadata). Technical metadata as described by the EXIF standard can contain fields for GPS data, like geographical latitude/longitude, altitude, and track. The Panorado Flyer tool enables you to get the coordinates of the place where the picture was shot and insert them into these fields. You can do it manually, using a dialog window. Or, if you have installed the Google Earth client (can be downloaded for free), you can search for the location there, drag it to the center of the map window, then change to Panorado flyer, grab the coordinates and insert them into the image selected, without typing any numbers.
Don’t think I’m going to do this terribly often, but certainly will consider it for future use.