On IBM's developerWorks site there's a new tutorial that wants to help you get started with ODBC in PHP, using the iodbc libraries and extension for PHP to connect to a database and pull back results.
Let's look at how a typical Linux-Apache-PHP-MySQL (LAMP) environment can be transformed into this flexible Linux-Apache-PHP-ODBC (LAPO) environment. There are two general options for ODBC drivers on Linux: iODBC and unixODBC. Both sets of drivers have their own pros and cons, and both work with PHP, but they work with different sets of databases. My choice is iODBC because of its traditionally strong connection to web programming languages like PHP and Ruby, as well as its stability in working with ODBC-friendly databases like MySQL and OpenLink Virtuoso.
There's a few steps in there to help you get the needed tools installed (linux server) to make the connection. Snippets of code are included showing how to connect to the server, run some simple SQL statements, fetch returned row information and do some basic debugging of the connection.