Hi

I've just ordered a Holux Cradle with built in speaker and GPS together with TomTom navigator 3 as part of a package for just under

 

Hard wiring is relatively easy - you can tap into spare terminals under the dash next the drivers right knee. Check out the links and pics on the tech faq (which explain how to hardwire camera detectors) - they are very clear. You'll need some auto 12 v cable, connectors, basic tools, but not much else.

TT3 is very good BTW, provided your PDA is fairly stable.

I mount my PDA on a cradle suckered to the bottom centre of the windscreen which I find OK - some prefer to mount down next the gearknob, or above the dash to the right of the steering wheel.

 

I have been using for sometime TomTom and it has been great. The following link details a hardwire install of my own. The only thing that I haven't sorted out yet is to improve the sound, although when you have the screen in view you don't really need voice directions. However, with the checkpoint software installed and the camera database the sound becomes more important.
I had previously tried the Seido cradle, but the sound from it was terrible and distorted. Also, having to plug the lead between the cradle and the PDA was a pain. The way I will probably solve this is to use Bluetooth.

My PDA install