Dave,
I am not personally familiar with the Sony unit, but I just read about it at Sonystyle.com.
It says that you can hook the unit to your computer via USB, so you could transfer your pictures easily that way. The unit has a 80 gigabyte hard drive, which should hold a heck of a lot of pictures.
That's what I do, only I use a Photovu which is an independant unit with its own screen and processor. I have a small portable hard drive hooked to it via USB that has all my pictures on it. If I want to add or delete pictures, I just move the hard drive to my computer and make the changes and then move it back to the photovu.
The photovu also has the ability to connect to a home network via ethernet or wireless so that you can stream pictures from a computer if you want.
If you didn't want to connect the Sony unit directly to your computer, you could transfer your pictures via flash cards, using either your camera or an independant universal card reader/writer (these are inexpensive and available at good photo or computer stores).
I would recommend connecting directly to your computer the first time you want to transfer a bunch of pictures because that is the quickest way to do it. Then when you want to add a few pictures to the Sony hard drive later on, you could use the flash cards to transfer them.
Hope this helps.