MySQL: Knowing the ID of a new record

[Pro2000]

Hello everybody.
I've created a PHP page that adds a new record to a table. I want to know what's the ID of that created record in that table.
For example:

mysql_query("insert into tableName(field_A,field_B) values('valueA','valueB')");

[Karthik_pranas]

You can use mysql_insert_id() function.
refer http://php.net/manual/en/function.mysql-insert-id.php

[Pro2000]

Thank you very much.. That's exactly what I want.