Use Sumif
if your Summary sheet contains, employees down the left side, starting at A2, and you have 2 column headers starting at B1 labeled Sales and Spent, then formula would be:
=SUMIF('Sheet1'!$C:$C,$A2,'Sheet1'!D

)
copied down and to next column.
Alternatively, you can use a Pivot Table, then drag Employee to Row label area, and Sales and Spent both get dragged to the Summation Area. This will autopopulate the unique employees and the respective sums.
Tutorial on Pivot Tables:
http://office.microsoft.com/en-ca/excel-help/pivottable-reports-101-HA001034632.aspx