Sorry, I was thinking of connecting a mysql database to access - different problem.
Forget earlier post.
Create an ODBC DSN using Microsoft Access driver (if you don't have such a DSN already) and specify that DSN's name in the connection with odbc_connect
$conn = odbc_connect('accessdsn', 'admin', 'pwd');
Use the other odbc_ functions to query the database, get results etc.