Hi Book Worm and welcome to the site!!
I'm a new Sony 505 owner also and a recovering bookaholic (the books had their own room in the last house and I had to get rid of about 1200 for the move--actually I could have brought them but the moving company wanted my other arm and leg to transport them
)
The best way to learn about your new ereader and what you can do with it is to just click on the forums and click on the Sony forum and just start reading... Also check out the Wiki tab.
But the very BEST part is all the beautifully formatted books that you can upload ( done by the dedicated members here ) and all the VERY helpful people on this site.
Go ahead and ask questions and someone with chime in and answer and/or point you to where you can find more information...
Have fun