Orchestra Conducting Course in Vienna led by Salvador Mas, called once a year from end of July to beginning of August.
Associación Ilya Musin, Orchestra Conducting Technique Course, with Maestro Ennio Nicotra. Two specially remarkable points on this page: the article ["Waving, not drowning", by Andrew Stewart from Classical Music Magazine]; and the section "About technique".
In Catalonia, Antoni Ros-Marbà usually gives courses and masterclasses on conducting, both in the Conservatorium of Liceu in Barcelona, and in the Escola Municipal de Música in Igualada: In this last place, it is usually called every two years, and the last time was in July 2009.
Internet shows us many places in Spain offering Orchestra Conducting courses, but I will only point out to one, that of the Escuela de Altos Estudios Musicales, in Huelva for its singularity, due to the fact that it consist mainly of studies at home, and only during 3 days in July you are required to travel to Huelva.