tempdb files and usage

-- space usage information for each data file in tempdb

SELECT *, 

(user_object_reserved_page_count)*8 as usr_obj_kb,

(internal_object_reserved_page_count)*8 as internal_obj_kb,

(version_store_reserved_page_count)*8 as version_store_kb

FROM sys.dm_db_file_space_usage

GO

http://msdn.microsoft.com/en-us/library/ms174412.aspx

-- tempdb files

SELECT * FROM tempdb.sys.database_files

GO

Troubleshooting tempdb Space Usage:

http://www.madeira.co.il/troubleshooting-tempdb-space-usage/