I haven't seen this posted yet, but if its a duplicate, I apologize.
I know many of us have been complaining about the lack of being able to scroll down by page. I think its been widely known that "t" takes you to the top of a page and "b" takes you to the bottom but I have just discovered that hitting the space bar scrolls down.
I'm not sure if this was something that was just not published or if RIM snuck this into an update.
I have 4.3 and pressing the space bar scrolls down. I went into the BB help menu and looked at keyboard shortcuts when I first got my Curve (about two months ago) and it was listed there.