I'm running on esxi(which has 2 physical NIC intern -extern) 2 Ubuntu 12.04VM's each connected to internal NIC. How could I bridge theme to have internet on both of theme without to use for each one an external IP. Is it possiblie to do this?
ESXi is not a firewall/router. What you're asking for is generally included with desktop virtualization products (VMWare Workstation, Virtualbox etc).
You need to think of ESXi as a simple Layer 2 switch. Any kind of fancy NATing / routing either needs to happen on a VM or on something external to the boxes. In your case, you should see up a vSwitch with one of your NICs and then connect that NIC to a NATing router.