Platform

Contacts

• Google
• Yahoo
• Zindus Add-on for Thunderbird
  

Calendar

• Google
• Yahoo

Mozilla Labs

• Sunbird
• Spicebird

Synchronizing Google with Mozilla on my desktops..

• Windows XP
• MacOS X
  
• Fedora

Thunderbird-with-Lightning

• Address Book sync with Google
  
• Configure for IMAP (and disable POP?)
• Provider for Google Calendar