Oracle Linux 6.1 guest on Virtualbox 4.1 can't connect to network

Given that Oracle Linux is heavily based on Red Hat Enterprise Linux, the network configuration is probably the same. If you didn't need to enter any network parameters during the installation of Solaris, then you're picking up a network address through DHCP. There isn't much call for doing anything else in a NATted virtual machine anyway.

To configure a DHCP client on RHEL, edit the file /etc/sysconfig/network-scripts/ifcfg-eth0 to contain the following lines:

DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes

Or you can use Network Manager instead (it'll give you the same kind of network configuration through a desktop icon that Solaris has, and in fact I believe it is more powerful than Solaris's — not that you really need that in a VM).