I have been following the instructions both in Pc-connectivity page (http://maemo.org/development/documen..._connectivity/) and a related post by greygoo (http://talk.maemo.org/showthread.php...t=ssh+password).

After creating the private / public key pair on my host machine I have copied the public key on my tablet (N900) and appended the content to two locations:

1. /root/.ssh/authorized_keys (username: root)
2. /home/user/.ssh/authorized_keys (username: user)

I am able to ssh in to my tablet from the host machine without a password as root, but not as user. When I ssh in as user I'm still being prompted for the password.

Could this be a permission issue with /home/user/authorized_keys?

You have wrong path here. Should be:
/home/user/.ssh/authorized_keys

Thanks for the notice, that was just a typo (corrected in the original post). Path is correct on my tablet.

the "user" account has been locked,you cannot do ssh login using this name

Problem solved, by creating a new user and repeating the steps I can now ssh the new user in without a password. Thanks!

you should probably use "ssh-copy-id" to transfer and add the key(s). That is theoretically more secure and certainly less error prone.

Sure you can - I do this all the time. You'll need to make sure the permissions on the .ssh directory and the authorized_keys file are set correctly (0700 for the directory and 0600 for the file).