For developers, here is a tool called Post Parrot. As a developer you can send POST variables to the sites home page and it echos back what was in the post. This is a great tool to help you debug. It also show the client IP and the headers that were sent.

Fast Form Testing
For super fast form testing, instead of just printing it out, or when you are testing a post that does not go to your own site this is ideal.

Particularly when you are sending a post to another site this comes in handy. Many basic tools exist out there that save a ton of time. If you are a developer this is one of them.