Greetings,
We did this once when we planned a trip and wanted to visit a lot of people along the way. It worked very well for us.
First, create a new Google calendar that includes your itinerary so far.
Then go to Settings and choose the tab for Calendar Settings where you will see a list of your calendars
Under the Sharing column you can edit the settings to make the calendar public, or to share it only with those whom you choose. You will have to provide an email address for each of the individuals that you would like to share it with.
Hope this helps.