HOW TO: Generate PDF Output On-the-fly

Solution 1: Use an open-source .NET PDF library. Sample list:

ASP.NET FO PDF at SourceForge.net - generates XSL-FO from DataTable to render PDF
iTextSharp at SourceForge.net
- Examples and Tutorial: http://itextsharp.sourceforge.net/
- Also see this article: Create PDF on the fly with .NET and iTextSharp by Valerio Fornito, DoPostBack.com
PDFCreator at GotDotNet - design PDF document visually using Visual Studio IDE
Report.NET at SourceForge.net

Solution 2: Use a commercial .NET PDF library. Sample list:

ABCpdf .NET by WebSupergoo - free license also available
Apoc XSL-FO by Chive Software - generates PDF using XSL-FO
Aspose.Pdf by Aspose
DynamicPDF by ceTe Software
PDF4NET by O2 Solutions
PDFLib by PDFLib GmbH
TallPDF.NET by TallComponents - able to create PDF documents either programmatically using an object model or from XML.
- Tutorial: Create and manipulate PDF documents - 100% .NET by Frank Rem (CodeProject.com)
XMLPDF by Visual Programming - converts XML to PDF

Solution 3: Use activePDF WebGrabber to convert any URL output to PDF on-the-fly.

Solution 4: Use a report generator like Crystal Reports or SQL Server Reporting Services to render to PDF.