[fjtorres]

No 6in reader will do a particularly good job on pdf.
Unless the pdfs are explicitly targeted at small-screen devices when created you likely won't be satisfied with the presentation.

You *might* be able to get a half-decent HTML file out of a pdf using the free Mobi Creator from Mobipocket.com (install it as the Professional version instead of the personal version to get the ability to import pdf). The Creator will produce a .mobi/prc file that will be Kindle-compatible *and* leave behind a fairly clean HTML file that you can use to produce a better prc conversion if you're not satisfied with the baseline mobi file.

You can test these files with Kindle For PC so you can get an idea of how your documents will look on the Kindle before spending money.

Just bear in mind that pdf is *not* and has never been a true ebook format but rather an electronic paper format. Think of it as a digital microfiche.