There is no "out of the box" way to simply say "take this dataset and turn it into a PDF" in ASP even in .NET there is no one control that can take an arbitary dataset and convert it right to a PDF. (Granted the ReportViewer control can export data from Report Files to PDF but that is over kill) Anyway I digress.
This is one of those secnarios where you need to look at Buy vs. Build. If this is for a personal project and you have the time to mess around and create a COM component or the like that can create PDF files, by all means have at it. On the other hand if this is a project for a client it is better for both parties if you just buy a component and call it a day. You will save your client money and you will save your self the stress of having to create said control.
Read this if you want to know how to get a correct reply for your question:
.: Wrox Technical Editor :.
Wrox Books 24 x 7