Hey Cobe, I'm a newbie too and these guys are great. Read the forums. Just take some time and do your research. I've only just started with the whole x10 thing and I will slowly be adding to the house, about $20-$40 a month, until the whole house is done. Here are my suggestions on questions you want answered:
1 - You are probably going to check out how the computer works with the system. Know what you have. Do you run Windows 7, Vista, XP or something older. Don't just buy, look and ask. Do you have a serial port on your computer? I got a firecracker serial interface, then looked at the laptop. I didn't have a way to plug it in to the laptop. Simple things like that will get you frustrated as you start trying things out.
2 - Not everything works in my house. Read the sites but I run into the typical problem of one side of my breaker box doesn't talk to the other side of the breaker box. This is very common from what I have read. If you are handy you can add a device to your breaker box for around $20ish dollars. If you are not electronically inclined, you can buy a device that bridges the problem by plugging into your dryer plug. It's around $70ish dollars. I was able to figure out my problem early. I had my Transceiver plugged into the living room. Worked great in the living room and hallway but would not run my appliance device in the bathroom or kitchen. I plug the transceiver in the bathroom and the kitchen would work but not the living room. I looked at the breaker box and sure enough, they are not on the same phase. This will be the first "fix" I do for the house before I purchase any more items.
3 - Do you use regular lights or CFL lights (the squiggley ones they are trying to get us to buy to replace the old ones). You cannot dim CFL bulbs. Don't try. 90% of my house uses CFL bulbs (they are much cheaper to use). I only have a handful of regular bulbs for the dimming light in the living room when we watch movies. Use appliance modules for these if you plug into the wall. You can search for other devices but my research takes me back to lamp modules for regular incandescent lights and appliance modules for CFL lights.
4 - I love the cheap $10 x10 remote (UR74A). My whole x10 world started because of this item. I have 5 remotes and the wife hates it. I was looking for a cheap learning remote. I found a few at Walmart but I came across the UR74A online and saw the x10 button. I did my research on what it did and here I am. Ultimately I wanted to have 1 button,the SAT button in my case, control my most basic functions. I setup the SAT button to turn on the TV and volume, control the channels and special buttons for my comcast remote and run the DVD play/stop/pause buttons. It took a little while to get the hang of it but I was able to setup each and every button exactly the way I wanted it to go. I was impressed for a $10 remote. Even if you don't get into anymore x10, try the remote out. Even the wife was happy with it.
There are many more things to talk about but these are the very beginning things I've dealt with over the past month. Everyone here has been helpful. Just look around, ask questions and be patient. You can get all your questions answered and find great deals on eBay and other places. Have fun.