Oh great now I have to attempt organization!
I've never participated in a swap so I really don't know how that all works, I guess everyone interested could pm me their addresses and I can put together a list and pm it back to everyone, and then we can all send a bead or two (depending on how many people want to participate) and blessing to the others on the list.
I don't think there needs to be any criteria for the beads... just something pretty that you enjoy looking at, maybe it gives you a certain feeling or the shape/material is symbolic of some maternal quality for you.
As far as blessings go, just a simple message- maybe a favorite quote or poem regarding motherhood.
Another idea is writing an affirmation on a nice piece of paper so the recipient could put it up like this lady did:http://www.gentlebeginnings.org/birth_affirmations.htm
The following texts may be inspiring as far as blessing-writing goes:http://www.artoflove.us/birth_texts.html
I guess that's about it... Anyone who's interested feel free to pm me your address and I'll start compiling the list. We'll see how many people are on board and decide on the amount of beads in a week or so.