No, that won't work. Only OmniFocus for Mac can sync with iCal. MobileMe just sees your OmniFocus data as a big blob of bits, not something it can turn into a calendar. So you'd need:
0) Sync OmniFocus for iPhone to MobileMe (or some other WebDAV)
1) Sync OmniFocus for Mac to the same WebDAV
2) Sync OmniFocus for Mac to iCal
3) Sync iCal to Google Calendar
0) Sync OmniFocus for iPhone to MobileMe (or some other WebDAV)
1) Sync OmniFocus for Mac to the same WebDAV
2) Sync OmniFocus for Mac to iCal
3) Sync iCal to Google Calendar