I find http://www.connectionstrings.com/ to be a great reasourse to help sorting this sort of thing out.
I have connected to Excel spreadsheets many times in the past but I used the following
connection string with the OleDb provider:
Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\path\file.xls;extended properties="Excel 8.0;HDR=Yes;IMEX=1"
You can actually "paste" that sort of connection string straight into the Connection settings window (into the item called 'Connection String') and the bits get sorted out into the right sport.
Do note with these ODBC and OleDb connections that you may need to install MDAC or similar, it can vary quite a bit between machine, MS Office version etc... I have not thried the above on Widnows 7 yet but have done so with Vista + MDAC...