Geocoordinates and database query

I would like three distinct software functions written and integrated into code for a website: 1. The site should use an api to translate location entries into geocoordinates and save them into the database. 2. Given the new coordinates, the system should query the database to find the other entries that are most similar based on proximity of start and end-points (ie minimizing the difference X2 - X1 and other simple arithmetic operations). 3. The site should have the capability to output driving directions for a route with a variable number of map points (3 - 10), using the google maps api. This should be written in PHP and integrated in to a WordPress 3 site.