See AmMin's special collections at http://www.minsocam.org/MSA/AmMin/special-collections.html (*new August-2015, update bookmarks). Additionally, special collection papers are identified in each issue on the Table of Contents.
Authors, submit your paper as normal (http://minsocam.allentrack.net). In the screen asking about Special Collections, please select from the pull-down menu. The help on that screen provides details about open collections and invitation only collections (you can always correspond with the special collection associate editor if need be). [Associate Editor contact data is available via http://www.minsocam.org/MSA/AmMin/aes/aelist.html (on the main MSA web site).]
To propose a special collection please contact Editor Keith D. Putirka.
All special collection papers go through the same peer review and editorial process as any other paper. They are published when ready and not held up waiting for other papers to finish. Instead the collection also grows virtually over time via the web. The virtual collection (as it grows) will be available for easy selection of papers and each year collections that have a "quorum" are available via MinPubs.org in PDF or print-on-demand formats.
Our special collection Associate Editors: