Yes, the dot underscore (DS_Store and ._ AppleDouble files) are gone. They have been replaced using SMB Alternative Data Streams (ADS) also known as NTFS Streams. See http://www.symantec.com/connect/articles/windows-ntfs-alternate-data-streams for  detailed information on ADS.

As a network administrator, I welcome this but it may have repercussions. For example, you have a bunch of Quark files without extension names on an SMB share in the AppleDouble format created by a 10.4 client. By default a 10.6 client wouldn’t be able to read the Quark files because it doesn’t read the AppleDouble dot underscore file and there are no extension names. Therefore, Apple have made it easy to re-enable the feature. This is possible be editing the nsmb.conf file.

To disable named streams as a default for your Mac OS X client user account

Execute these two commands in Terminal:

echo "[default]" >>  ~/Library/Preferences/nsmb.conf
echo "streams=no" >> ~/Library/Preferences/nsmb.conf

To disable named streams as a default for all Mac OS X client user accounts on a Mac

Log in to Mac OS X with an admin user account if you aren’t already logged in as an admin, then execute these two commands in Terminal:

echo "[default]" | sudo tee -a /etc/nsmb.conf
echo "streams=no" | sudo tee -a /etc/nsmb.conf

See the man page on nsmb.conf for more details about how to configure it.

To re-enable streams on 10.6 or to enable it on 10.5 change streams=no to streams=yes