I did tons of research on carbon offset companies in both the US and abroad (UK, EU, Canada) and found Terrapass to be the most userfriendly, especially for gift giving. I was going to use the Carbon Neutral Company, which is probably the best in terms of effectiveness, transparency, etc, but not user friendly in a gift-giving sense. It is geared toward investors or individuals who are offsetting their own use -- and the governance is top notch. However TerraPass allowed me to calculate the flights of my significant other, who travels often, and for the holidays I offset two flights to come visit me! So it was really cute...and TerraPass is pretty transparent, and sends a newsletter every week or so.
Adri M.'s keywords: gift, user friendly, carbon neutral