Migrating from PPC Macs to Intel Macs:
and this article:
How to use Migration Assistant:
Troubleshooting Firewire target disk mode:
For your new Mac you should get a Thunerbolt to Firewire conversion cable.
Another option you can consider is the option to make a Time Machine backup of your old Mac onto an external drive, and use that backup to migrate the files onto your new Mac. Read > http://support.apple.com/kb/HT1427
I suggest you not to transfer applications. Most of them are probably PowerPC apps so they won't work in your new Mac