Seed Envelopes from Blossomswap just click on this link and choose one of many listed. This site offers two sizes for envelopes. I generally use the small (group of 3) for saving seeds unless they are squash seeds, then I use the larger envelope.
Here are a few more of my favorite sites:
Alenkas
Angelfire
Seed Site
"He who sees things grow from the beginning with have the best view of them."
- Aristotle
Rain Drops Keep Falling On My Head... click to hear Burt Bacharach