I've been involved with Home Automation to some degree over the last few years. I've dabbled with zWave and installed a small home network to some success. zWave is a good technology - its mesh networking capability and bi-directional signalling is superb but the chronic lack of devices and support in the UK has really crippled its success and with it my enthusiasm for it.
However, a new DIY project (fitting a new kitchen) meant an opportunity for more automation and by pure coincidence I happened upon the HomeEasy range of automation products that B&Q stock. They had exactly the things I needed to automate the kitchen under cupboard lights and kickboard L.E.Ds - a wireless PIR sensor and sockets and all at a very good price, the starter kit (3 sockets + remote) was £20 and the PIR about £11. Now when I walk into the kitchen from dusk to dawn the lights automatically switch on and switch themselves off 1 minute after leaving the room (this can be set on the PIR to 5s, 60s, 5m, 10m)...perfect!
I can recommend the HomeEasy range if you want a simple, cheap automation system that is easy to setup. I've had the odd situation where one of the sockets does appear to not receive the power off command from the PIR but its pretty rare - possibly related to the battery power in the PIR. There are plenty of fancy switches, remotes and even an outdoor specific range. The "ultimate" range even boasts SMS integration with a special base station that can convert SMS messages sent from your mobile to commands beamed around your house!
What is missing is PC integration, however - this is where xPLMonkey appears to fit in. I say appears as I've not been tempted to try this myself but the xPL site mentions support for the HomeEasy range. Using USB tranmitters (transceivers?) connected to a PC you can control HomeEasy receivers - eg: send commands to switch them on/off/dim. xPLMonkey acts as an abstraction layer to convert scripting commands into wireless automation commands. There is even support for MediaCenter!
So if you want to start your wireless home automation somewhere then HomeEasy seems like a decent and cheap enough place to start - xPLMonkey can sate in the inner geek in you if you want to take things further and combine automation with your PC - this obviously opens up more interaction possibilities like web control.
Another range that offers almost identical automation products is DomiaLite - very similar to HomeEasy (or rather HomeEasy is similar to DomiaLite as I think this was around first). Domia offers PC/Web integration with a dedicated controller unit but I think there is a subscription fee involved. Worth a look though....
If you do get HomeEasy working with xPLMonkey then drop me a line - I'm curious to hear about your experience with it!