What software tools do I need to build Facebook apps? Is this going to be expensive?
The good news is that you can get away with entirely free software to build your app! The bad news is that there’s only good news. So, I guess that’s just good news, then! Phew.
Until Facebook released Facebook Open Platform, you couldn’t build Facebook apps locally on your own computer because you needed the Facebook servers and parsers and other crazy software running. Now you can download Facebook Open Platform, which is licensed under a combination of the Common Public Attribution License (CPAL) and Mozilla Public License (MPL), get it running locally on your dev machine, and go to town. So, I guess there used to be a piece of bad news (you always needed to have a web connection available to test with), but it’s now a mostly good piece (you can get it running locally if you’re good at the server setup and software-compiling-type stuff). You can find out more about Facebook Open Platform at http://developers.facebook.com/fbopen/.
Other than that, you’ll need a text editor for writing code, an FTP client for uploading it to your server (see Hosting for more info), and some sort of graphics editor for images. If you have a toolkit in place for doing web development now, you should be more than ready.
I’m not going to cover getting Facebook Open Platform running, since that could be almost a book on its own given the number of possible operating ...