php mysql compare long and lat, return ones under 10 miles

You probably don't need to do this in code, you can probably do this all in the DB. if you use a spatial index. MySQL docuemtnation for spatial index

EDIT to reflect your edit:

I think you want something like this:

SELECT *, ((ACOS(SIN($lat * PI() / 180) * SIN(lat * PI() / 180) + COS($lat * PI() / 180) * COS(lat * PI() / 180) * COS(($lon - lon) * PI() / 180)) * 180 / PI()) * 60 * 1.1515) AS distance FROM locations HAVING distance<='10' ORDER BY distance ASC

VIA: http://www.zcentric.com/blog/2007/03/calculate_distance_in_mysql_wi.html: