First, you'll want to geocode all your addresses and get the lat/long for them.
Once you have the lat/long, there are several ways to determine which ones
are within a 5-mile radius of a given lat/long point.
You could calculate the distance from each point to the center using
the geodist() function, and then subset where that distance <= 5 miles.
http://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a003113162.htm
Another alternative - you could create a circular map area with a 5-mile radius,
and then use Proc GInside to determine which of the lat/long points are inside
that circle. Here is an example demonstrating that technique:
http://robslink.com/SAS/democd29/customer.htm
http://robslink.com/SAS/democd29/customer_info.htm