One book I found was "Decorating with Interior Trim", a Sunset book. I ended up choosing a craftsman style design; very simple. Photo at http://www.billb.name/diy/openWall.asp . Bill

"Where will I find the materials for the jamb? " Plain old 1x lumber ripped to the correct width is all you meed. The casing trim covers the joint between the edge of the jamb and the finished wall. Depending on the age of the house and the wall type it could be easy. Older plaster walls may have used metal forms the plaster was applied over to create the shape. Cut plaster. remove forms, repair plaster. A little messy but not that hard (unless you have textured plaster walls). Drywall walls can be shaped like this in many ways, but there will be a header over the opening. You just demo the corner wedges and then repair any wall damage that will not be covered with jamb or casing trim.

So, the breezeway originally was the entire depth of the house, but the back end is now laundry/enclosed area? I think screening the front would be nice, especially if you have a nice view out front. We had a breezeway and they made the front part a bedroom and the back a mudroom/passage to the kitchen. They kept the windows and door across the front and people do mistake that door for the front entrance, but what can you do? I'm a porch person, so I say go for the breezeway. We would have liked to revert, but ours is a very large bedroom with very large closet (attached to HVAC) and it would make the house three bedrooms, instead of four. Your room doesn't sound like it has a very practical function as it is so I say, go for it!

It opens to this hallway. I think the section between the 2 might be load bearing, but Id have to confirm with a structural engineer. Definitely, there are several metal column posts in crawlspace running down the length of that wall. Kitchen opening is load bearing. I had thought of completely walling over one opening - probably the one in the middle, next to kitchen Pic of hallway.