What calendars sync with an iphone-other than outlook

None, but you can sync the iPhone with CalDAV calendars over the Internet.

iOS: How to transfer or sync content to your computer

You can sync calendars with:

• Microsoft Outlook 2003, Microsoft Outlook 2007, Microsoft Office 2010 (Windows XP, Windows Vista, or Windows 7)
• iCal (Mac OS X)
• Microsoft Entourage 2004, Microsoft Entourage 2008
  Note: If using Microsoft Entourage, use Microsoft Entourage 2008 12.1.2 or later if syncing with Mac OS X v10.6 or later. If you would like to sync data on your Mac with Entourage, enable syncing between Entourage and Address Book.
• Microsoft Outlook 2011 for Mac
  Note: If using Microsoft Outlook 2011 for Mac to sync calendars you must update to Microsoft Office 2011 for Mac Service Pack 1 or later.

For example, here's how you setup a Google calendar to your iPhone with CalDAV -> Sync your Apple device - Google Calendar Help