During my third lengthy period of post-Sauder MBA unemployment I made a bunch of web mashups using PHP and various APIs and web services. I used PHP as I knew it was available on my webhost. I don't recommend PHP as a software development language unless you have no other option or you can leverage a large amount of existing code, for example all the open source code I link to below.
If you want to make web mashups you can use my code as I've made it available here. It is pretty much unsupported and definitely provided 'as is'. To use it you will need to get some other PHP working and get permission to use the following APIs.
I still recommend these older instructions and following those steps to get my and other people's code to run. Below are links to the very latest versions of the PHP I wrote as well as other code I used: