Using T-SQL to Query a File System Folder

You can use xp_cmdshell.

Example:

EXECUTE master.dbo.xp_cmdshell 'DIR "C:\YourDirectory\" /A-D /B'

There's a good, full example with more options here.

CLR integration is also an option, if you're not comfortable with allowing xp_cmdshell to be executed.

See MSDN.