WebAPI Software
There is not a single solution for using web APIs. Because there are no standards, many companies implemented web APIs using their own solutions, even proposing new solutions. This is a new and hot topic, currently under development and innovation.
For this reason, different APIs are using different solutions. Sometimes, API provider offers averything you need, as a download of some files to be installed or just a simple copy-paste solution , with wizards to build it. Other times, you may need scripts or software from third-parties.
For time being, we'll offer only PHP examples, in near future we'll have also ASP & ASP.NET.
One software you may need is Dietrich Ayala's NuSOAP. This is an open-source SOAP implementation for PHP, you can use for APIs that require SOAP access. There are a few files to copy on your server, and then, there is only one file to include in your pages when using it: nusoap.php. You'll see later how to use it.