So many choices to make! ... starting with your "Save the Date" card, then invitations and envelopes, announcements, programs and place cards. In making your paper choices here are some things to look for:
1. recycled, handmade, or plantable papers processed chlorine-free and printed with vegetable- or soy-based inks
2. tree-free paper made out of hemp, banana stalks, bamboo, kenaf, or organic cotton
3. a printer who will use paper with a high percentage of post-consumer recycled content
papers that aren't metallic or plastic-coated, characteristics that make them hard to recycle
4. opportunities to reduce paper use, like sending a postcard (instead of multi-enveloped notes) for your save-the-date, or using online invitations and a wedding blog to let people know about the bachelor/ette parties, rehearsal dinner, and gift registry

Here are a couple paper/invitation companies you might like to look at: Twisted Limb Paperworks and Green Field Paper Company. Also, be sure to ask at local stationary and party invitation shops for green options... hopefully by now they're offering some. It's always great to keep things local when you can. Thanks for taking steps to have a greener wedding!