Q:_WA_Sys_out... - What are these? I find a lot of these in the SysIndexes table ?

Answer:

Sometimes sp_helpindex tablename returns entries like: (ex. _WA_Sys_test_status_6CD31A51) in addition to the user created indices. But these are not visible in enterprise manager when we check the indices for a particular table. These aren't indexes.

It is system generated statistics over a non-indexed column. They are generated because you have the "Auto create statistics" option turned ON in the database property.(Or sp_dboption 'auto create statistics'). Generally these are harmless and its good to have them. But in case if you need to drop them use:

DROP STATISTICS '_WA_Sys_test_status_6CD31A51'.

More details can be had from the BooksOnLine topic 'Statistics'. Just to add on to the above example you can create a dummy table with say 1000 records without creating any indexexs. If you query for this table in the sysindexes table you willfind a single entry denoting it is a heap. Now access this table on some columns data as a range scan. You will find that SQL Server sees that this table doesn;t have indexes and hence would create such statistics for its internal purpose.