I've been able to transfer all 400 of my contacts to the N900 from Fedora12 KDE Kontact and the Akonadi database.

I simply exported all contacts to a single .vcf file in 3.0 format.

Next I just used Dolphin and entered fish://user@192.168.0.11/. It asks for the password for user on the N900, which I entered. Then I browsed over to /home/user/MyDocs/tmp and dragged the addressbook.vcf file over and dropped it.

Almost instant! 175K of contacts copied. Then I imported the contacts into the Contacts app on the phone.

You have to get root access prior to doing this and setup the password for 'user' and 'root'. You also need OpenSSH on the phone (that's what makes the fish:// protocol work in KDE).

This simple thing has just made the N900 pay for itself. I love it. Now my phone is connected to my Linux desktop.

I can also see the photos in DCIM directly via wifi without copying them over to my computer!

Seriously cool!!

Hope this helps someone.