Automatically open ICS files in Google Calendar

Lots of web sites have an option to export events as an ICS file that can then be imported into a desktop or web-based calendar (for example if you're invited to a Facebook event there will be an export button that gives you an ICS file).

By default in Firefox 3.5 on Vista I'm only offered three options here "Open with Windows Calendar", "Open with Other" or "Save File", so what I'd do is save the file onto my PC, and then log into Google Calendar and import that ICS file.

What I'd like is to have an "Open with Google Calendar" or "Import to Google Calendar" type option when I click the Export link.

I know that you can configure Firefox to send mailto: links to GMail, and I've got the Operator extension installed that will detect hCalendar microformat entries embedded in the text and offer to import them to Google Calendar, but I can't work out how to configure either of these to do what I need.

Preferably I'd do this without installing any additional software, and in a way that will work with a Google Apps account (but if someone can point toward a solution for normal Google Calendar's that would be a good start).

I found a final solution to this! I based it off of the code to add Gmail as a mailto: handler, and adapted using information taken from Google Chrome's preferences file:

javascript:window.navigator.registerProtocolHandler("webcal","https://calendar.google.com/calendar/render?cid=%s","Google Calendar");

To use it, just go to Google Calendar, open Firefox's Web Console (Ctrl+Shift+K), and paste it into the code box.

I have created a small .NET application to do just that. If you associate the .ics extension to this application, whenever you either double click a .ics file or click a link to one, this application will import it to the google calendat that you configure, and it works with google hosted domains.

I know that you prefer a "no software" solution, but maybe this could be of use to you.

It is available at: http://gcalicsimporter.codeplex.com/.

iCalendar is not a microformat so I'm afraid Operator isn't going to help you here. So you'll need a separate Firefox extension or helper app to do this. I'm not aware that one exists and Google was no help when I searched. Sounds like a good development opportunity.

Workaround: save the .ics file to disk, then create a draft email in Gmail. Title it whatever, Attach the .ics file. Save it and go to the Drafts view. Now you should see a calendar icon to the right of the draft email you created. Click it to add the event to Google Calendar. Simple, eh?

Update: I'd go with Alejandro's .NET solution if you have that option.