My new favorite FireFox plugin:
https://addons.mozilla.org/en-US/firefox/addon/636
It converts any page to a PDF, and since it's an online service via a FireFox plugin, it works as well on Mac OS X, Windows and your favourite flavor of Linux.
Once transferred to the reader, the result works very well using the combo of FullScreen & PageFlow mode! I'm consistently impressed how well PDFs work on this thing, even though it's still my least favourite format. The same file on my Sony reader: I'd have to be pretty desperate to read it like that.
Below a couple of shots, taken in the brightest morning sun. Try that with an LCD screen!
The second one shows PageFlow in action: that black line is where otherwise an unfortunate pagebreak would be.