This script will convert a CSV file to a bookmark.txt file for use with Navit. To convert from vCard, it can be used with the vCard to GeoCSV Converter script.
The CSV should look like:
name,latitude,longitude
"Doe, John",40.2553,-60.1552
The resulting bookmark.txt looks like:
mg:-60.1552 40.2553 type=bookmark label="Doe, John"
The script: geocsv-to-navit.py
Note that Navit may automatically convert the coordinates to hex values the first time it runs after using a bookmark.txt file generated by this script.