Hello txdiniu and welcome to MobileRead. I have the Sony 505 and love love love it. Start checking out all the threads to learn about your Sony before you get it. There are lots of free books here for your Sony and a few authors you will meet in the forums also.
You can download books in the LRF, epub, and PDF format just to be ready for your new Sony.
(I believe that you can download the Sony software ahead of time so you can read your books on your computer) Someone let me know if this is correct
Jump in with questions and the friendlies around here will chime in with answers or point you in the right direction.