Easiest way:
Use FireWire Target Disk Mode. Shutdown your PB. With a 6-pin/6-pin FW cable, connect the PB to the up-and-running eMac. Boot the PB while holding-down the "T" key (for Target) until the yellow FireWire logo appears on your screen. Release the key, and the PB drive will mount like a FW drive on her eMac. Drag and drop.
I'd have her export her iMovie editing as a full-quality DV clip (File>Export>QuickTime>Full Quality>DV). From there, you can drop it into your timeline.