If you don't need dynamic destinations (like the above post points you to), just create an OLE DB Connection Manager for your Excel sheet using the Jet 4.0 connection and point to the Excel spreadsheet. When you do your Data Flow Tasks, you can then connect to different sheets by using the OLE DB Destination and Data Access Mode of Table or View. Then the name of the sheet comes below that.

I recommend using stored procedures called via SQL Command in an OLE DB Source for your Data Flow Task rather than embedding the T-SQL directly in the task. Not only is it a little faster performance wise, f you have to make changes to your code, you only have to make it in the database instead of changing your SSIS package and re-uploading it every time.