1. Install the required packages:
sudo apt-get install kdepim-dev kdepimlibs5-dev libqt4-dev libical-dev libcurl4-openssl-dev libglib2.0-dev cmake
2. Download the source code of kcaldav in: http://code.google.com/p/kcaldav/
3. Compile and install:
4. Start korganizer. You will be able to add CalDav calendars.
5. To configure a caldendar from google, the most tricky thing is the URL which must be:
Replace the google_calendar id with the corresponding ID, which can be seen in its properties in Google calendar.
Replace the @ character with %40
Include the final slash in the URL