Online dictionaries
Croatian http://hjp.novi-liber.hr/index.php?show=main
Croatian http://enhr.dict.cc/
Serbian http://recnik.krstarica.com/e/
“Serbo-Croatian” or Bosnian, Croatian, and Serbian, compiled http://www.asusilc.net/finalpro1.htm

Croatian http://riznica.ihjj.hr/

Online resources for learning Bosnian, Croatian, Serbian,  and Montenegrin and for learning about these languages
Simple description of the orthographies of the three languages with a table of letters

“Established in 1999 and operated by Duke University, the Slavic and East European Language Research Center (SEELRC) has as its mission the improvement of the national capacity to teach and learn Slavic and East European languages.”
Link to the BCS page: http://seelrc.org/webliography/bcs.html

A Handbook of Bosnian, Serbian, and Croatian by Wayles Brown and Theresa Alt © SEELRC 2004. This resource is located on the SEELRC site.

Bosnian, Croatian, Serbian: A Grammar by Ronelle Alexander; and Bosnian Croatian, Serbian: A Texbook by Ronelle Alexander & Ellen Elias-Bursać

An online matching game for learning Cyrillic cursive letters

Orthography generally
The Library of Congress ALA-LC Romanization Tables give guidance as to how to transliterate other orthographies into Roman type.

Opportunities for further education, conferences, calls for proposals
Stanford University, Center for Russian, East European and Eurasian Studies, “External Opportunities” page – listings: https://creees.stanford.edu/opportunities

Southeast European Studies Association – “a scholarly, non-profit, non-political organization devoted to the exchange of knowledge amongst scholars interested in the area of Southeastern Europe.” The SEESA blog features conference announcement, calls for proposals, travel opportunities, etc.

The Association for Slavic, East European, and Eurasian Studies (ASEEES) – “dedicated to the advancement of knowledge about Central Asia, the Caucasus, Russia, and Eastern Europe in regional and global contexts.”