You can use the OpenRowset function to open the excel and select its content as if you were selecting from a table.
INSERT INTO YourTable (Col1, Col2, ........)
SELECT Col1, Col2, ......
FROM OPENROWSET('Microsoft.Jet.OLEDB.4.0','Excel 8.0;Database=C:\YourExcel.xls', 'select * from [Sheet1$]')