PDF Hammer lets you tweak PDFs sans software
Reorder and combine PDFs to your heart's content with PDF Hammer.
Ever had a PDF file or two laying around that needed some minor tweaks, but you didn't wanna fork over the cash for a full version of Adobe Acrobat, or install some other PDF application such a rare task? Give PDF Hammer a look. The service lets you do simple page re-arrangement on PDFs of all sizes, and when you're finished it'll spit it out as one big, beautiful file. The service is pretty simple to use, and lets you upload multiple files without losing any rearranging or deleting progress you might have made. You can also see a picture preview on the left hand side, although it's a little too small to read text.
My major wants for version 2.0: a zoom function, drag-and-drop (for rearrangement and uploading), and a print button so I don't have to even bother saving the file when I'm done.
Having worked in the printing industry before heading to Webware, I can tell you this isn't a replacement for a complete PDF editing and authoring program like Acrobat Professional or NitroPDF, but it's simple enough that I think anyone could use it for some quick adjustments, especially while away from their home machine.