IBM and Sun recently announced that IBM System x and BladeCenter will be able to run Solaris, and the two are also working to get Solaris to run on the mainframe.
So is Solaris on Power that far behind? Obviously Sun is committed to its open-source vision for Solaris, and getting Solaris to run on as many systems as is humanly possible. Will IBM allow Solaris to run side-by-side alongside AIX and i5/OS? I think Solaris and i5/OS could happen quicker than Solaris and AIX just because Solaris and AIX are the two major competing Unix operating systems right now.