Software for Google imagery workflow (DigitalGlobe visualization to GeoTIFF file).

Step 1. Generate set of landmarks in KML format for Google Earth application with PlaceMaker 2 application (by zed), according to guide.
Step 2. Open landmarks in Google Earth 5.2 (or Google Earth 6), select landmark layer and "play trip" to download all desired area to application cache.
Step 3. Extract information from Google Earth cache with CacheMaster 2, saving in SAS format.
Step 4. Use SAS.Планета 110216 application to visualize area in base of cache content and to merge image fragments (tiles) for selected area into entire image, save image in BMP format, and georefferencing information in any text format. Use information from SAS GIS site.
Step 5. Use gdal_translate application from FWTools 2.46 to assign georeferencing and convert image to GeoTIFF format.

Reference information on Хитрости Google Earth site.

P. S. SAS.Планета and some other applications requires russified windows to represent GUI in the correct form, even if you select English as interface language. To deal with it I installed virtual machine (Microsoft Virtual PC) with Russian version of Windows XP.