iTextSharp is a C# port of iText, and open source Java library for PDF generation and manipulation. It can be used to create PDF documents from scratch, to convert XML to PDF (using the extra XFA Worker DLL), to fill out interactive PDF forms, to stamp new content on existing PDF documents, to split and merge existing PDF documents, and much more.

Several iText engineers are actively supporting the project on the iText mailing-list itext-questions@lists.sourceforge.net and on StackOverflow: http://stackoverflow.com/questions/tagged/itextsharp