Hey, glad you like them. Here is a tutorial that I made for them in case you want to try your own. Sorry about the juvenile images- I made it in Illustrator because I am now out of bubble wrap and can't show you through photos. Let me know if this doesn't make sense.
For supplies you will need:
- Decorative paper that is medium to heavy weight (scrapbook paper, wrapping paper, etc)
- Bubble wrap (the standard kind, not the stuff with the giant bubbles)
- White glue, or a heavy-duty glue stick. (You can also use permanent scrapbook adhesive tape)
- Clear tape
-Scissors or paper cutter
-Ruler
-Spray adhesive (optional)
Step One:Take a piece of decorative paper and cut it to be 11 x 9 inches.
Then, fold it following the graph below. (This is for an evelope that is 5x7, for a bigger envelope just double the width and add an inch for the "flap" on the side, and allow .5 in on the bottom and 1.5 in on the top for flaps also)
Step Two:Cut off the pieces marked in the diagram

Your paper will look like this:

Leave on the table right side down for the following steps.
Step Three:Cut two pieces of bubble wrap that are approximately 4.5 x 6.5 inches (slightly larger is better than too small)
and glue, bubble side down (so the smooth part faces towards you), to the wrong side of the paper inside the two 5x7 inch pieces. (The part without the pattern) Leave about .25 inches on each side.
I glued mine with spray adhesive, but white glue will work ok for this. Be patient and let the glue dry if you use white glue. AND spread white glue thinly so the paper doesn't get wrinkles and warp where the glue made it too soggy.
Step Four:Once the glue is dry, use clear tape (packaging tape or scotch tape work fine) to tape down the top edge of the bubble wrap as marked in the diagram. This keeps it from peeling up when you fill the envelope.
Step Five:Put glue on the bottom two flaps of the paper and fold the envelope together. Press the bottom flaps together firmly and allow to dry. These will be secure if you used good glue, but if you are worried you can tape this seam. Your envelope will be connected on the bottom, but open with a 1 inch flap on the right side, and a 1.5 inch flap on the top like this:
Step Six:Put glue on the side flap, and fold over, securing it to the back of the envelope. For additional security, tape the flap as well. (This one likes to peel up otherwise!)

Now your envelope is done! Fill it and either glue or tape the top flap shut. If you have a solid color, dark colors, or busy pattern, you will want to affix white mailing labels on the front to write you addresses on it. If you make some of these, I'd love to see pictures!
Happy mailing.