Hi thadocg...
Well for starters... You probably won't need a dedicated PC. Nice right? The ioBridge module is standalone and just needs a pathway to the internet to operate. And judging from what you said, I'd say that you would start with the io-204 module (the brains), a temperature prob and probably the X10 board to control lighting and fans. The soil moisture is a DIY type thing (maybe a terminal board?). And oh, as for the web cam. Again, this can be done without a PC. Get a network cam. I kind of like the cams that I use for TankedCam because they work pretty good and are pretty cheap (refurbished) on eBay. Its the Panasonic BL-C1A. But you may want to look at PTZ (pan, tilt, zoom) cams too. I found this page kinda cool to start exploring network cameras (some are really expensive though)
http://www.securityideas.com/demos.html .
Just make sure you do your homework before diving into this. A couple things that I learned quick. X10 will not work if it has to "jump" from one circuit to another. Both the X10 transmitter and receiver should be on the same physical circuit. Also, I found that some PTZ cams (such as the BL-c111A) look as if it could be wall mounted or just sit on a table. Which it can but, its viewing area goes in a straight line out and below. It does not go up any higher because its intended to sit high up in a room and look down. I had to actually mount the camera tilted backwards just to be able to get the area I wanted. Not a preferred method. So these are just examples of what you may encounter.
Lastly, the ioBridge site is capable of working with an iPhone to control things. But if you want to do anything custom. You would need your own web server or space on an existing server. Many ways to deal with that.
Good luck and keep asking questions. We all hover around looking for problems to solve. :-)
Cya...
