If searching manually, you'd have to enter a date range such as 6/1/2011...6/30/2011.
In a script, you can use a set field step with a calculation to find all records in the next 30 days:
Enter Find Mode  //clear the pause check box
Set Field [YourTable::DateField ; Get ( Currentdate ) & "..." & Get ( CurrentDate ) + 30 ]
Set Error Capture [on] //keeps no records found dialog box from interrupting script when no records are found
Perform Find 
script is nice...thanks
I think it's off by one and needs to use + 29 instead of + 30. With + 30, you'll include July 1st in the find.