The Dell SC440 has a Broadcom BCM5754 NIC, which isn't supported by the Ubuntu 6.06.1 server CD. You have to build the server without a network interface, then copy the new driver source onto it using a USB drive and build and install the driver.
I'm building Ubuntu on this server to run VMWare Server, so I also was particular about the disk partitioning. I created a 4 GB partition for root, then let it partition the rest itself. It made partition 5 the swap with 6.1 GB (I have 2 GB of RAM), and the rest of the disk on partition 2 (143.7 GB), which I put on /usr/local. I changed the usage of the file system to "largefile4" to give one inode for every 4 MB. I don't really know what that's going to do to performance, but it seems to make sense given that I'm going to be creating VMs there.
Next I followed the instructions here to build and install the driver. The instructions worked perfectly (with the usual 50 percent "forget to sudo" rate).
The I edited /etc/dhcp3/dhclient.conf to send the hostname:
send host-name "vmhost01";
And restarted the network:
ifdown eth0; ifup eth0
Then next time my DNS refreshed it got the server name.