In a DATA step, you would use the appropriate INFORMAT with either an INPUT statement or INPUT function to parse the character string to a SAS numeric variable that represents a "date" (important for choosing your INFORMAT).
Then you must convert the "date" variable to be a "datetime" variable likely using the DHMS function - my preference.
Here's a general example that reads a date character string in a particular input format, converting to a date, and then assigning a new variable as a datetime:
format mydate date9. ;
INPUT mydate yymmdd8.;
format mydatetime datetime21. ;
mydatetime = dhms(mydate,0,0,0);
The SAS support http://support.sas.com/ website has technical documentation and supplemental conference and sample papers on this type of topic - I have provided links below for reference.
var1 = 'Nov 30 2008 12:08 AM';
INPUT_VAR_DT_MM = input(scan(var1,2)!!scan(var1,1)!!scan(var1,3), date9.);
put INPUT_VAR_DT_MM= INPUT_VAR_DT_MM= date.;
This will give you a SAS date (not datetime)!