How can I transfer data from a G5 iMac to an i7 iMac?
Does the migration assistant work well across OS versions and CPU architectures?


Yes, this will work just fine. The best way to do it is to get a firewire cable to connect the two iMacs, boot the older iMac into Target Disk Mode, and let the installer on the new iMac perform the migration.

I believe that Rosetta isn't installed by default, but when you try to launch a Power PC app you will be prompted to install it.