I got my Nexus one the second it was available on ATT. I previously had an iPhone 3g. In my car, I had it mounted with a proclip mount, the swivel one. I used the Kensington LiquidAUX made specifically for iPhone for charging and audio.
When I got the Nexus One, I was afraid I'd need to buy a new mount. I found the Nexus One fits just fine in the proclip swivel mount! I just had to change the dock connector from the proprietary apple one to the micro usb. Luckily, the proclip swivel mount was designed for the end user to mount the end of the cable themselves. (I'm not sure if I'm explaining this clearly) I used this mount I replaced the Apple connector with a micro usb and used some shims to make sure it was centered. With this setup, my Nexus One can charge in my car, in it's proclip cradle.
Just a Note: I tried using my cigarette-to-usb power adapter that was included with a bluetooth headset to power the N1. It was not powerful enough, If the screen was on for Nav or whatever, It wouldnt charge. I got this one and it works much better. The key is, I think, is to have a 1Amp charger.
Currently my audio is connected from the headphone port right into the aux input on my 2009 Altima stock radio. It works okay but it a bit unsightly. I ordered a new Kensington LiquidAUX that will utilize the N1's audio over bluetooth. An Amazon commenter says it works great with the N1 so I guess I'll see.
The LiquidAUX should arrive today. I just need to wait for a 90? audio cable extension to connect the the LiquidAUX so when it's plugged into my radio it looks nicer. (This is an optional step, however, as the LiquidAUX comes with the necessary extension but is a straight one and sticks out off the radio too much for my taste) Here is the cable.
When all is said and done, I'll post pictures. Maybe I'll make this post its own thread.
When I started this post all I wanted to say was: "An iPhone 3G mount from proclip will hold a Nexus One" Looks like I got carried away. Hope this helps some folks.
-Chris
PS: Oops, this is my first post and I can't insert links. I underlined things that should have been links. I'm not sure if an exception can be made in this case. When my project is done I'll make sure to post pictures and links on my blog.