Ok I use the thunderbird email client with the calendar in there called lightning. I love it but you can't sync that calendar with the iphone. The iphone can sync with the google calendar. I now found out a way to keep using my calendar in thunderbird and being able to sync it. Thunderbird has an extension called Provider for Google Calendar. This allows you to sync the two calendars together. When using thunderbird and I make an entry in my calendar it automatically makes that entry in google calendar....with that in mind that means you can sync google calendar to your iphone and still use the thunderbird client and its all up to date. Pretty cool. It just like me syncing my thunderbird to the phone.
Here is how to do it. How To Integrate Calendar In Thunderbird And Sync With Google Calendar
Now my question.....whats the best way to sync the google cal to the iphone. I have been reading up on a few wireless methods.
Edit: I used a free exchange called nuevasync! It works flawlessly! I can enter a date on the phone and it shows up in thunderbird and vice versa!