Query to result XML execution plan in SQL Server 2008 out of SSMS

You can use the SET SHOWPLAN_XML ON. It needs to be executed as the only command in a batch. Then if you execute subsequent queries, you will receive XML plan for them instead of executing those queries. To disable the XML plan you execute SET SHOWPLAN_XML OFF.

SET SHOWPLAN_XML ON
GO
Your query
GO
SET SHOWPLAN_XML OFF
GO

Details related to the SHOWPLAN_XML are hre on MSDN: SET SHOWPLAN_XML (Transact-SQL)

This will give you all execution plans in the cache and a lot of statistics about the execution, like total/min/max IO/CPU/execution time etc.:

SELECT * FROM sys.dm_exec_query_stats qs
    CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle)