The Kindle can be used to read non-DRM PDF document. BUT there is no reflow capability provided. Reflow improves readability, for example by increasing the font size and reducing the number of characters displayed on each line so that the whole line can be displayed on the Kindle screen without needing to pan left and right.
HOWEVER, Amazon provide a free service to convert PDF documents into Kindle format, which can then be reflowed, with a selection of eight font sizes. Just email the PDF document as an attachment to amazon (the address in given in your Kindle account details) with the word “convert” in the subject box. Within a few seconds you will receive a notification email from Amazon informing you that the document is ready for download. Once downloaded on your computer, connect the Kindle to the computer using the USB cable provided. The Kindle will appear as a drive. Just drag the downloaded file to the Kindle “drive”. You will now be able to reflow the document and set the font size as you please.
If you get stuck, see Help on transferring PDF to Kindle.
A bonus is that you can then use the Text to Speech to have the converted PDF document read out to you.
On the downside, the conversion works best if the original PDF has a simple layout and may not convert well if there are footmarks, endnotes, images or columns.
If you do not wish to exchange emails with Amazon, an alternative method is to use the freeware Calibre to covert non-DRM PDF (and also non-DRM ePub) files into MOBI format. This can then be reflowed and read aloud using text to speech. Calibre also has many other features including collection management, and is well worth checking out.
If you read a lot of PDFs and find this all too cumbersome, you should also consider an ereader with builtin PDF reflow capabiliy (e.g. the Sony PRS 350 or PRS 650 may) be the best choice for frequent PDF readers, or a large screen ereader so that reflow is not necessary (e.g. Kindle DX) and would provide a display of footmarks, endnotes, images or columns. For more details see the ereader reviews on our eReaders Comparison.