I coded up a program that monitors my google voice account and sends x10 commands based on my predefined macros. In other words I now have a (free) way to control my house devices via text message!
I've only used it to send text msgs but in theory voice msgs should work too depending on how well google can translate
Since google voice is now free for those in the US more you out there might be interested in playing with it. There's no client program requirement -- you just need to be able to send a text msgs (or leave a VM). The program runs on your computer and currently uses a com port interface (CM17A, firecracker). If anyone out there wants a copy, let me know and I'll find a place post/host the code.
EDIT: I made a site for the software:
www.starbotcontrol.com. I'm in the process of making a better version: GUI, usb (CM19A) support, etc. To anyone out there who really wants to use this, I'm open to enhancement requests.
EDIT: A USB version is now available at starbotcontrol.com download area.