It seems like /etc/iftab is gone on (x)ubuntu 7.10.

In fact, it is… but the mapping is now handled by udev.

So if you want to assign persistent names to devices, just fire up an editor with the file

-$ sudo nano /etc/udev/rules.d/70-persistent-net.rules net.rules

and you will see something like this:

udev-rules for network mapping

Change the entries of the appropriate macs to something you like. I changed the name of my wired lan (eth0 above)  to lan1 and my wireless lan(eth1 above) to wlan1 as I like to start counting with one.