SurferTim:
Why do you need Twitter if you have your own Apache server?You can't host the Apache server on localhost alone. You can only access it from the computer it is installed on. It must be exposed to the internet.
I just use Twitter so I can text commands to my computer from anywhere, I couldn't think of a better way to do that (especially because I have a 'dumb phone'). Even running Apache 2 on my local network, the .php file I use will grab data from my Twitter account, and create a webpage on my network (I guess I didn't mean localhost I'm sorry lol) displaying the 5 most recent tweets to my account.
I didn't host the website on Arduino because trying to host a server, and process commands on the same board takes around 28kb of the 32kb alotted if I remember right. It's been a while since I've read in to that however, I could be way off. It would be super awesome to have a completely stand-alone Arduino home automation set-up that could read commands texted to it =)