The VERY REAL problem with Access and PHP is that you cannot work with access without a DSN. Meaning you cannot do DSN-less connections. Now, if you want to create 1 DSN for EACH .MDB file, that's ok.
And you have to use the ODBC functions for PHP to communicate with that database. Use the ODBC driver from Microsoft for Access.
I recommend to go to MySQL, nonetheless. Access is a bit crappy actually. 🙂
Hope it helps
fLIPIS