This doesn't mean the end of the port. All it means is that it's not part of the official team's projects. There is a team that came together to make sure that the "unofficial" PowerPC port will parallel the x86 port to the best of their abilities. Case in point, when Feisty came out, the update for PowerPC computers came up one day later in the Update Manager (even the ISOs are available). Consider that there are a lot of people that are running Ubuntu on PowerPC, especially PowerPC Macs. So long as they decide to continue the port, PowerPC will still be there.

https://launchpad.net/~ubuntu-powerpc

And if not, there's still Debian/ppc which is well-supported.

Remember that Canonical said that if there is still a high demand for the PowerPC version, they may reincorporate it as an official release. Let's hope this is enough for them to do just that.