Here are contact details for some overseas societies specialising in Russian philately.
Based in the US, The Rossica Society of Russian Philately is an active society. They publish the Rossica Journal of Russian Philately and their website includes the 'Samovar' discussion area.
The CSRP closed in 2009. The archive of its journal 'Post Rider' is available digitally through Rossica. There is more information here.
The Worldwide Society of Russian Philately aims to foster and promote the exchange of philatelic information relative to the Russian Empire and related areas of collecting. The Society is international in scope and non-political in nature. The WSRP website includes some online displays and a catalogue of new issues.