1) Acid Free Foam Core - I do NOT recommend that awful sticky mounting board, I've seen projects that were put on that years later, and they have a tendency to be discolored, pulled away when the adhesive gives out, and generally not very lasting.
I second this, although I use acid free mount board instead of foam core. Foam core makes the whole thing very thick, and it can be hard to find a frame with a rebate (the bit the glass and picture sit in) deep enough. I have some pieces that I had framed for me some years ago and the framer used sticky mount board, much to my disgust, and they now all need washing and re-mounting to get rid of the sticky residue and remove the wrinkles.
2) Pin or Lace - this is how you need to decide how to mount your piece onto the foam core.
I lace - crochet cotton is ideal for this, it's nice and strong. Lacing is the thing that takes the most time, but it is worth the effort. It'll take me about an hour to lace a really big piece. Pinning it first to get it straight is also worthwhile. I generally lace it tight enough to very slightly bow the board so that when it's flattened in a frame, it gives a nice smooth surface.
3) Matting OR a spacer - which depends if you are putting glass in the frame. IF you use glass, you do NOT want the glass to sit right on the stitching, so either matting or frame spacer should be used.
I always use glass to protect my stitching. I don't recommend acrylic, it's too easy to scratch and scuff. I also always use a mount, and sometimes two if there's beading. If you look at my Bird of God in the gallery, I framed that myself with two mounts, just because it looked better that way.
4) Frames - If it's something I've put a lot of work into, I'll get a custom frame made, (see BoG again) and they'll usually do a mount to fit, if you ask. I can't give you any online recommendations for that, because I'm in the UK so I use UK suppliers. For smaller things, I'll just use a frame from our equivalent of Hobby Lobby (or the local 5 cent store, I'm not fussed about where it comes from). If you do that, though, check the way the frame is put together carefully. Some frames have space for pictures to just slide in - you won't get a stitched piece in that space - you need the frames with little metal tabs holding the back board in place. I also recommend getting some acid free brown paper tape to seal the back of the framing. I'm pretty sure that you can get that from Hobby Lobby, too. I believe that either Hobby Lobby or Jo-Anns will cut mounts and glass to fit for a small fee, too.
Good luck! Framing is not especially difficult, but it is time-consuming, and of course, that is why it's so expensive to have done professionally.
Emma.
www.emmasenchantedworld.wordpress.com