I make several reports that are basically the same with the exception of the selection criteria. Sometimes I place these criteria directly in the Select Export or in a formula which I reference from the select Expert. Rather than muddling with the same report every time, I would like to simply have it reference an excel spreadsheet for the desired parameters. How do I go about this?

I dont believe you can do it with Crystal Reports isself. There are third party tools such as CRD by ChristianSteven Software that allows you to use data driven packages to accomplish this.

I did not understand what you wanted but ,i tried to point the data source to an excel file.
I created a new connection based on oledb-->Microsoft.jet 4.0 OledbProvider and selected the Excel file and in the
DatabaseType Dropdown i selected the Excel 8.0 ans selected the sheet in which i provided my values

for ex
ParamID ParamDesc
1 a
2 b
3 c
4 d
5 e

it created a database fields based on the Excel.Now i think you can use the same fields to make them as paramaters.
Try this solution.