you could write a simple app in QT, be it using python or c++, to query a webservice api with some key value pairs.
Since you have php/my_sql experience , setting this online api wont be such a task.

all the app needs to do is take an input ( if needed from the user ), then generate a network request to your webservice that will return the result back to your application.

thats just an overview, perhaps you already thought the same, any more details you need ?
there are plenty of apps that query online services in maemo and that are open source.