Ok guys, ive finished working on my carpc, got some pics posted below. Comments and constructive criticism appreciated..here is a little summary.
OVERVIEW
The car is a 2004 BMW 32Ci Sport bought 2nd hand in Australia. The car came with the 16:9 widescreen NAV monitor, but without the OEM satellite navigation. The car however did have a tv tuner. I have kept the OEM monitor in the dash and have installed the pc under the cd changer in the boot, hidden from view. I have seen the many installations of touch screen monitors and surrounding fabricated mountings in the dash, but decided to steer clear of this approach even though touch screen wouldve been nice and the quality and resolution of the lilliput and xenarc's is much better than the OEM. I guess i was more afraid of hacking into a $70 000 car than some others
So the pc includes:
Morex cubid 3688 mini-itx case
VIA EPIA SP-13000 motherboard
Seagate 60 gigabyte HDD
Geil 512MB PC3200 DDR memory
M1-ATX power supply
Linksys Wireless network adapter 802.11g
Pioneer slimline DVD Writer.
Software consisted of microsoft windoze
and a little peice of freeware called carx, which can be found here
http://carx.dl.am/
I should also mention that i purchased Rolf Reslers IBUS interface.
http://www.reslers.de/IBUS/
This enables one to control the carx software using the knobs and buttons on the OEM headunit/monitor- No need for keyboard and mouse!
As far as video output was concerned, i used the s-video out from the motherboard, and used a an s-video to composite cable to bring the composite input into the two relevant pins in the tv tuner. Audio signal was brought into the oem speakers sing the 3.5mm audio line-out from MB and into an aux input which i had previously retrofitted begind the dash. the cable was run under the door sills, behind the glovebox and into the aux input behind the dash.
M1-ATX power supply was used: positive to positive terminal battery, negative to car ground and white switch to one of the white ignition wires leading to the radio unit in the boot. Works like a charm.
So basically the pc starts several seconds after i put the key in the ignition, if i want to see the carx screen (front-end) i have to scroll thrugh the OEM main menu until i reach AUX (by pressing the mode button). this IBUS message puts RTS to high, and the carx screen takes over, and the audio from the aux in starts playing. I can scroll through my mp3 collection using the knob on the right hand side, and the buttons on the multi-function steering will still work..
this project has taken up a lot of my time, but i have to say it was all worth it in the end. there were several instances where i thought that i had fried my cars OBC, but the worst i did were a few flat batteries..I can tell you its not a nice feeling

when you go to start the car and nothing happens, not even the ticking over of the starter... i shat myself on several occasions, because ive heard the BMW IBUS system is worth tens of thousands to replace!!
The other thing i would like to add is that before i started all this i was a complete NEWB. I knew nothing!! the only thing i did know was that you must always search before asking simple questions... I did SO much reading, so much searching and surfing the net. I used both google and the search function on several of the forums including this one and e46fanatics and also the yahoo group hacktheibus. Of course i asked a few questions along the way, and in hindsight, the answers seem quite obvious, but i know what you Newbies feel , at times this all seemed like a foreign language and i just wanted people to say things in plain english. All i can say about this is read, read it again the next day, than a few days later, etc etc, and if you only absorb 10% each time you will eventually get there. Ill stop my ranting now!
Im happy to field any questions anyone has. I will try and check back here often, even though my project is finished. So without further ado, here are the pics....
as i mentioned earlier, feel free to comment..