Decimal or Point Data Type for storing Geo location data in MySQL
You could use MySQL's spatial extensions with GIS.

In a code example from Google displaying points on a map, they state:


  When you create the MySQL table, you want to pay particular attention
  to the lat and lng attributes. With the current zoom capabilities of
  Google Maps, you should only need 6 digits of precision after the
  decimal.
  
  To keep the storage space required for our table at a minimum, you can
  specify that the lat and lng attributes are floats of size (10,6).
  That will let the fields store 6 digits after the decimal, plus up to
  4 digits before the decimal, e.g. -123.456789 degrees I wouldn't worry
  about performance differences between numeric types. Decent indices
  will have a far greater effect.


You could also try DECIMAL as @gandaliter suggest. 


  DECIMAL is the MySQL data-type for
  exact arithmetic. Unlike FLOAT its precision is fixed for any size of
  number, so by using it instead of FLOAT you might avoid precision
  errors when doing some calculations. If you were just storing and
  retrieving the numbers without calculation then in practice FLOAT
  would be safe, although there's no harm in using DECIMAL. With
  calculations FLOAT is still mostly ok, but to be absolutely sure of
  8d.p. precision you should use DECIMAL.
  
  Latitudes range from -90 to +90 (degrees), so DECIMAL(10,8) is ok for
  that, but longitudes range from -180 to +180 (degrees) so you need
  DECIMAL(11,8). The first number is the total number of digits stored,
  and the second is the number after the decimal point.
  In short: lat DECIMAL(10,8) NOT NULL, lng DECIMAL(11,8) NOT NULL
  This explains how MySQL works with floating-point data-types.


Related information:


MySQL and GIS, GeoIP: FAQs, How-To, Articles, Blogs
Creating a Store Locator with PHP, MySQL &amp; Google Maps
Using the new spatial functions in MySQL 5.6 for geo-enabled applications