Can I transfer my phone contacts to my Gmail address book for use on my PC? I spent a lot of time organizing my contacts on my Galaxy S (Android 2.2) and want to know if I can transfer them to my Gmail address book on my PC. My PC OS is Ubuntu 12.04 and my Gmail desktop client is Thunderbird.
Absolutely. If you've synced your Android device with your Google account, your contacts would automatically show up on Google / Gmail Contacts.

If all your contacts are saved as "Phone Contacts" and not "Google Contacts", however, they will not be synced. You need to export the Phone Contacts and then import them into Google Contacts. It might be helpful if you adjusted your settings from within the contacts app to automatically save new contacts as Google contacts instead of Phone Contacts.