Here is how I solved the problem with some explanations. (Basically the same as it's been answered in all the previous threads).
Problem:
Original var: has data that looks something like... 20070131
I want var to look like this: 01/31/2007
data new;
set old;
new_var = input (put(old_var,8.), yymmdd8.); <-- put(old_var,8.) changes the old_var's data type from numeric to character. Then, the input function changes old_var into a SAS date.
format new_var mmddyy10.; <-- after it has been changed into a SAS date, then you have the option to format it any way you want. The mmddyy10. gives me the appearance I want (01/31/2007). I believe if you would like it to be 01-31-2007, instead of mmddyy10. you can use mmddyyd10.