I installed the official Honda iPod adapter at the weekend, which I had bought from Holdcroft Honda for £129.99
To fit this into your Civic, you do need to dismantle quite a lot of the dashboard as the adapter unit box is mounted on the back of the glovebox (for cars without Nav) or on top of the glovebox (for cars with Nav)
My Civic doesn't have the navigation system so the following steps relate to a non-nav equipped car.
I have to say that the installation manual which came with the kit was pretty comprehensive, with sets of instructions for LHD & RHD cars and the different bit for nav/non-nav equipped cars.
I also referred to the previous how-tos in the following locations to help in stripping the dash, and to save repetition I won't go into all the minute details as these threads cover all the initial dismantling.
To help in removing the dash panels, I used a plastic gap spreader that I already had which was used in fitting a Brodit Proclip into my last car - basically a very thin wedge of plastic which could be pushed into the panel gaps and could be used to lever the panels off without damaging them.
The following parts of the dashboard need removed before mounting the iPod unit.
Rear Centre console
Drivers Side end of dashboard
Lower panel of dashboard under steering wheel
Silver trim round gearlever
Lower centre console (Removel all covered in Pottsy's thread above)
Panel above radio/vents - I covered the radio/aircon display with duct tape to stop it getting scratched while removing this panel
Radio comes out with 3 screws at top, and two bolts at bottom (Covered in Roger Harris's thread)
There are also two harness clips, one for the hazard warning switch and another for one of the radio cables which need unclipped before the whole headunit can be removed.
Removal of complete glovebox - covered in Swindon Japster's thread.
Once all these bits have been removed (took me about an hour), the installation of the actual iPod kit can begin.
On the back of the glovebox are some fins which need cut off as per the photo below. The lighter grey lines are where the ribs used to be. The iPod adapter fits vertically between these fins. A couple of holes are drilled through the iPod adapter brackets into the glovebox and the adapter is held in place by bolts (covered with plastic caps) screwed through from the glovebox.
The following picture from the installation manual shows the location of the adapter, along with routing of the two cables along the top of the glovebox (held in place by sticky foam covered pads)
The glovebox is then refitted into place, with the cables run through into the space behind the radio (for the cable which plugs into the headunit) and into the space above the centre storage box (for the cable which plugs into the iPod)
The cables for the iPod adapter are cable tied at various locations to the existing wiring harness, just leaving enough cable to reach the back of the headunit and into the storage box compartment.
Next a hole needs made into the top of the centre storage box. The instructions say to use a 15mm holesaw and cut two adjacent circles towards the back left corner of the storage box as per the following photo.
I didn't use a holesaw, but drilled several smaller holes with a 6mm drill and cut & filed roughly the same shape out. This hole is not visible once the installation is complete, and is covered by a rubber grommet anyway.
Here is another picture from the installation manual showing the location of the holes which need drilled.
Next, the headunit is refitted, taking care to connect all the plugs back in, with the iPod cable being connected to the CD changer port. At this point, I plugged my iPod in (before securing the headunit in place) to check that everything was working. Once this test had been done, the radio was screwed back into place, the centre console was refitted and the panels under the steering wheel and across the end of the dashboard were put back.
In all, it took me about 3 - 3.5 hours to fit the whole kit, although I was taking my time particularly during the dismantling as I didn't want to damage any parts of the dashboard.