If you are putting the SD into the new G2, just access them from there.
If they happen to be apps, you can install the apk files from the card to the device.
So any Music, Photo, Video files, just leave them on the SD card, same for Ring tones. Just organize the folders so you can find things easier when pointing other apps to them.
Anything on the sdcard will be found under sdcard/ on the sdcard.
You will not want to stuff your device memory with media files, photos and ringtones anyway.
Or if this is an older card and you want to use the newer gig card, use a card reader or the phone that they are in now, and use the USB cable to connect the phone with the SD card in it, so it will act like a small hard drive and just copy everything from the first phone to the new phone (drag and drop) to either the desktop into a folder, and then hook up the G2 and drag and drop that folder to the SD card (takes about 4 to 10 mins), depending on the amount of files that need to be copied and the speed of your computer. I do this most of the time as it's the fastest way to do bulk file copying from phone to phone.
Or you can use Bluetooth file transfers from phone to phone, normally this is pretty slow if there is not a batch transfer option between the two phones.