This query should help

select top 10

t1.session_id,

t1.request_id,

t1.task_alloc,

t1.task_dealloc,

(SELECT SUBSTRING(text, t2.statement_start_offset/2 + 1,

(CASE WHEN statement_end_offset = -1

THEN LEN(CONVERT(nvarchar(max),text)) * 2

ELSE statement_end_offset

END - t2.statement_start_offset)/2)

FROM sys.dm_exec_sql_text(sql_handle)) AS query_text

,(SELECT query_plan from sys.dm_exec_query_plan(t2.plan_handle)) as query_plan

FROM (Select session_id, request_id,

sum(internal_objects_alloc_page_count + user_objects_alloc_page_count) as task_alloc,

sum (internal_objects_dealloc_page_count + user_objects_dealloc_page_count) as task_dealloc

from sys.dm_db_task_space_usage

group by session_id, request_id) as t1

INNER JOIN sys.dm_exec_requests as t2

ON t1.session_id = t2.session_id

AND t1.request_id = t2.request_id

where t1.session_id <> @@SPID

--AND t1.session_id > 50

order by t1.task_alloc DESC

You can find the original for it here:

http://blogs.msdn.com/b/sqlserverstorageengine/archive/2009/01/12/tempdb-monitoring-and-troubleshooting-out-of-space.aspx