If you're opening the reports from CRS, you'll need the BI Platform SDK to create a login token and then create an OpenDocument URL that will open the report for viewing. OpenDocument will allow you to set parameter values as part of the URL. See http://help.sap.com/bobip, click on "Development Information", and download the second file ("Viewing Documents Using OpenDocument") to get more information about OpenDocument.
If you want to be able to schedule reports, you'll need to use the BI Platform SDK. You can find some sample code for doing this on my website at www.dellstinnett.com/sample_code.html. Look for the BOEScheduleCrystal assembly. The code is older (XIr2 and VS 2005), but the techniques are the same for the latest SDK.
-Dell