PDF Rider is a GUI for "pdftk" and allows you to make some simple manipulations to PDF documents. It is written in c#/.net 3.5 (WPF), with the aim to be simple and user friendly.
PDF Rider is made upon the utility pdftk and can be used to:
* Merge PDF documents * Insert pages from another pdf file * Extract pages from a PDF document to a new document * Delete pages * Rotate pages * Crypt and Decrypt a pdf file * Burst a document into single pages
PDFRider uses a web browser control to render the pdf file. In this way you can view the pdf file with your standard reader (Adobe Reader, etc...) as you do inside a browser!
From http://pdfrider.codeplex.com/ :
"CodePlex is in read-only mode in preparation for shutdown. See shutdown, migration, and archive plans"