Is this one DateTimePicker or two?
If it's one:
1. Create a date parameter in your report.
2. In the Select Expert, set the date field in your tables "is equal to" the parameter you just created.
3. In your code, set the value of the parameter to the value of the DateTimePicker prior to displaying the report.
If it's two parameter, repeat the steps above for the second date.
-Dell