I'm running Ubuntu in Snow Leopard with VMware fusion 3, and I want to be able to access the wireless network on eth1 within Ubuntu so I can run tools like aircrack-ng. However, the bridged network that VMware sets up connects my Airport interface in Mac to the wired interface eth0 in Ubuntu. How do I set it up so that the Airport interface is connected to the wireless interface eth1 in Ubuntu?
Unforunatley what your descrbing is not possible. Vmware can ONLY pass USB devices from the host to the guestOS. The wifi card in your mac is a pci device, and cannot be passed thru to your guestOS, ubuntu sees eth0 as a real hardware nic, though in reality it's vmware bridging your hosts connection and creating a virtual device that ubuntu thinks is real.
If you really want to use wifi in a VM to try aircrack and the like then you will have to buy a compatible USB wifi device ( search the backtrack Linux distro forums for an idea of supported hardware ) and you will be able to pass it thru to your guestOS with no issues.
Hope this helps :)