Hi,
You can import sightings into Diary from just about any source. What is required up front is to get the data into Diary Sightings import format. This information can be found on this site under "Support :: Online Users Guide", go to the Windows book on the left and then choose Import/Export Window. It gives you details about the Sightings import format.
So, all Handheld has to be able to do is to export sightings into some textual or CSV/spreadsheet format.
Let me know if I can assist with any of this or if you have any further questions.
Jeff |