You may need to enable wins on the samba server and install libnss_wins.so. It may be installed with the samba-client package. Then add "wins" to the "hosts:" line in /etc/nsswitch.conf file:
hosts: files dns wins
Enter the samba server's IP address in the wins entry for the dhcp server. ( I use a linksys router. )
There may be a /var/adm/fillup-templates/samba-client-dhcp.conf file that modifies the smb.conf file for other linux computers. You may need to enable it in a /etc/sysconf/ file somewhere. ( This may be distro dependent however )
This may allow you to ping the netbios hostnames.
An alternative is to run a local dns server for name resolution. I only have 2 or 3 hosts up at a time at home and just keep my /etc/hosts current if there are any changes.
If you don't have very many hosts, and you run your own dhcp server, you could configure the server to give the hosts a certain IP address, based on the MAC address. Then you could use an /etc/hosts file and not have to worry about it not being current.