Using the ODBC driver seems to require opening a port on your server (usually 3306). If you do not control the server your ISP may not want to open this port.
There is another way - Using HTTP commands. I am experimenting with this using the Turbo Professional "Internet Professional" package. It has a component that lets you issue http commands programatically (this may or may not be a difficult roll-your own project; I haven't looked into it too deeply. Also there may be other components that let you do this.)
If you include some variables in the URL you can Easily pass information to an PHP script using SQL to INSERT, UPDATE, select etc.
In my case, I have the SELECT return comma-delimited records on a minimally formatted html page.
Security would probably be a concern, depending upon what you are doing. I'm looking to see if the Turbo Power component can do secure web site stuff. Then all the data transmitted would be encrypted.