API:GuildHousesWar GetRegisterCount

Returns the number of guilds currently registered for the next Siege War battle. NOTE: As of October 15, 2010, for North American servers, the BETA Siege War has a maximum limit of 240 guilds.

Example of how to display the number of guilds currently signed up for Siege War. DEFAULT_CHAT_FRAME:AddMessage(tostring(GuildHousesWar_GetRegisterCount));