I'll put some pictures up when I borrow my friends digital camera ... might be a couple of days from now.
Basically, what i've done is bought a female 5.25" connector, the kind of one you would usually solder to a printed circuit board, and run short leads from the original jack socket to this new one. (This is all done in the little area which has the volume pots in it)
I then plugged an AKG Wireless guitar bug into the new socket and fitted it securely inside the compartment. This is definately available in the UK, not sure about the rest of the world though.
The 'Bug' requires power which is usually supplied by a single AAA battery. Obviously I didn't want to take the back plate every time I wanted to change the battery so I bought a battery holder and fitted that inside the area where the trem springs are, in between the springs so they wouldn't clash. The plate which covers the springs has two holes in it which let you see the springs...however, if you turn it around it, magically it is in the right place to slot a battery through! I used an AA battery holder so you could slot the battery in and get it out easily--it doesn't fall out though! (I find you can 'pop' it out by using the locking trem Allan keys!)
I then drilled a hole through into the trem compartment from the electronics compartment and ran the power cables through (quite thin-- it's only 1.5V). In series with this I added a switch which I mounted on the electronics compartment plate which lets you switch it on and off. I also drilled another hole which lets you see the little status light on the bug.
Anyway, it works extremely well. Battery life really isn't a problem -- you buy up lots of cheapish batteries and replace them before any gig etc....but then again you would do that with pedals wouldn't you? Signal quality is great and there is a volume control on the receiver so I have matched the output volume on the wireless and the jack lead.
This is only a cheap guitar so I didn't do much. I think what I'd do with my next guitar is use a push/pull pot to turn it on and off or it automatically is disabled when you put a jack lead in...I'll have to see. Any other ideas?
-lamby