Matt Zimmerman, chairman of the Ubuntu Technical board, posted a message regarding the future state of Ubuntu on the PowerPC architecture (the one the PS3 is running).

Beginning with Ubuntu 7.04, the PowerPC edition of Ubuntu will be reclassified as unofficial. The PowerPC software itself and supporting infrastructure will continue to be available, and supported by a community team.

So basically development on Ubuntu for the Cell architecture is up to the community now, due to a lack of funding and resources. But as Zimmerman writes:

It is possible that PowerPC will once again become a fully supported architecture in the future, if the resources needed to guarantee its quality are found. The architecture is certainly gaining large numbers of users in embedded and console devices, and there are many reasons to continue to work with the platform.

I’m sure the Ubuntu community will provide some excellent releases. And if Ubuntu keeps gaining ground among PS3-users, this might make it worth some official support again in the future.

See the Ubuntu Wiki page for arguments and the Launchpad page for a list of current team members.