PHP-Freaks

I have a list of students entered into a mysql table using the following fields: id, name, surname, address, towncode, streetcode, Another two tables has been designed so to normalize the schema: One is the Streets table streetcode, streetname, towncode .. and the other one is towns with the following fields: towncode, townname Now i need to design a form using php to filter students depending on the town (I select using the SELECT element of a form) , and as well on the street (I select using the SELECT element of a form) which fall under that town. Can someone help me out with this issue. Sorry but I am new to PHP!!!!!!!