Selecting a subset of imported property addresses from a map

[Egan Lohman]

Anyone have advice on how to achieve the following:

I have a list of leads in excel.  I bought this list from an online list source.  It contains property address, owner name, etc..  But it's a full list for an entire city.  I want to target leads in a specific area.  So I need a way to import my full list to a map view (like google maps), and then be able to select just the markers that fall within a few square blocks.   Google maps lets me import no problem, but I haven't found a way to export just a subset of those leads.  Anyone found software or an online tool that can do this?