I am looking for software that will read PDFs and web pages aloud for me under OS X 10.5, preferably something that is free.

I am aware that you can make your Mac read to you by pressing a key combination. It is pretty slick, but I really want something that:

• will allow me to say, "Read this document" and let me skip paragraphs and pause (instead of simply stopping and then restarting from the beginning)
• will allow me to skip things that aren't relevant, like page headers, footers, and side bars.
• will allow me to rewind and listen to something again (either to think on it more deeply, or to understand what the text-to-speech engine was trying to say)
• for a pdf with text in two columns, will let me read just one column at a time. (Right now if I make a selection, it gets both columns and reads from one and then from another. If I could just select one column and read it, I'd be happier. [IIRC, Apple improved things in Snow Leopard so you can select one column in a pdf.])

I don't really expect one program to do both pdfs and web pages, but it would be nice.