Amazon updated Kindle firmware for PDF support the other day (and other improvements, like enhanced battery life). It should have been installed by now on your kindle if you had the wireless switched on. You can manually install the update from here (http://www.amazon.com/gp/help/customer/display.html?nodeId=200324680)
With this you can read PDF natively on kindle, however I found few caveats:
- You can't change the text size in a PDF document as you can do with default kindle format.
- You can change the orientation though, which is good.
- The PDF loading is slower than the native kindle format.
- The text brightness is not as good as with documents in native kindle format.
Still exploring... but the PDF support is actually very beneficial. Hope Amazon can improve it with future updates.