ASP.net (VB.net) & Google maps

I want to use google maps in a immo website, written in asp.net (vb.net) and sqlserver 2005 (i write the site by my own, I ONLY need assistance for the GOOGLE MAPS part) So I will provide a site with houses for rent all over the world. What I'm asking: > put 5000 dummy address all over the world in a databse > make 1 input form Fields: name of the house/user, address line 1, address line 2, zip code, city, country, x-coor, y-coor >> save this data in the database (address + geo coordinates) - also the X-Y coordinates of this house (user) example Colaba Causeway 123, Colaba, Mumbai, India Show these addresses on google maps [login to view URL] you zoom on mumbai all the address in mumbai have to be loaded and show (see [login to view URL]) 2. If you click on the pointer of the house, a small detail will be visible so you can click through the page of the house (i will make by my own) (zie [login to view URL] bottom of page) 2. if you put an circle on mumbai the houses in mumbai have to be loaded (see http://nl.eurorelais.be/zoeken/#corsmap=open&cors=50.00773901463687c9.931640625c50&output=json) The width of the circle has to be managable. >> max 400 addresses in 1 time on the map (because of performance), You also have to show the number of houses who are on the map in a certain moment the more you zoom out the higher the number, this has to be 5000 if you zoom to the max (but max of 400 house pointers on the map, random ordered) (use ajax to zoom in out and show number of houses)