XML Web Service Integration

I run a website for a National Ticket Broker. We are by no means a huge company. In order for us to offer more inventory than we actually stock we are part of a nationwide 'exchange' of ticket brokers. We link to a national database of tickets provided by other small brokers all over the country. This information in this database is provided to us via an XML Feed (located here: [login to view URL] ). I need to know how to interact with this XML Feed using the webservices. I know that I am supposed to use a "SOAP Request", but I do not know how to do this. How do I send the SOAP Request, how to I recieve the XML information from the SOAP Request? From what I understand of all this, it should be fairly easy (I imagine just the code that I could then plug into my site). What I expect in the end is the working code to put in my site and brief instructions on how to use it. I will be able to format the resulting XML myself.