I've just bought the Garage Band Jampack Symphony Orchestra - mainly so I can use those software instruments in Logic. The loops are already there but how do I transfer the software instruments from Garage Band to Logic... Any ideas? A

You don't have to transfer them--they should appear in your Logic software instruments when you click on the input of the channel strip. The file path will be: Stereo/Logic/Garageband Instruments/(choose instrument)