We don't have the plan for .ics files in the immediate future, but we aren't far off having Outlook integration between Outlook calendars and Method Calendars, as well as Outlook emails to CRM activities and cases. :)
iCal, if it is still needed, isn't that hard to pull off, though. In fact, you could easily do it using the MethodAPI and Method.
1. Create a webservice that accepts 2 paramters, the Activity.RecordID and the email to address.
2. Edit a Method Calendar and add a calendar event so that it calls your webservice and passes over the RecordID to the webservice and the email address of the user the job is assigned to.
3. Your webservice needs to simply call the MethodAPI for that RecordID and easily build an .ics file, and email the ics file as an attachment. Done.
ics files are easy to make:
SUMMARY:You have a new Method Work Order #123
LOCATION:125 Job Site Rd, Vancouver, BC.
DESCRIPTION:Park around back and don't put the ladder on the front of the house, use the back.
See, it would be a fun project that would take an hour, tops, for a developer to make.