Many Thanks, ladies, to you both, for responding.
I'm actually not needing to mail these, but needed them for the inside of a CD folder album I'm making (and realized I was all out of the little mini envelopes I needed for the inside portion.) I have heard though that USPS won't mail the little 3x3 card sizes.
Valerie - thank you so much for the details on making the envelope. I did actually search here on SCS to see if there was a tutorial somewhere, but I couldn't pull anything up that fit the bill. I also googled but couldn't find the exact size I needed - so I so appreciate the details you provided!
Now...on to mini envelop making!
Thanks again!