Thank You tuxsavvy, that's the exact info I was looking for!

I wasn't aware, that N900 already contain connectors (szame on me, I thought I've gone through whole wiki "N900 hardware modifications" page!), I was planning to solder my own ones... Knowing that they are there, eliminates IMO the hardest part, so it's blazing great info!

As for drilling PCB, it's not good idea, cause it's multilayer - unless You find spot that You're 100% sure doesn't contain paths, and You're very careful, when drilling through layers of shielding and glass-epoxy.

I would rather thought about using free space near battery connector - if i remember correctly, hole is big enough for at least 2 cables. Even if not, modding N900 plastic cover is no problem for me, could even try make it (connectors at cover surface) good-looking

Of course, I was thinking mainly about GSM and WiFi - information, that GPS connector is also available make me really happy penguin