The following article describes how you can create a proxy page that converts a SQL Server Report into a PDF file. When the code is executed, it will make a call to a report on a SQL Reporting Services Server, generate a PDF file and then present it to the user as an option download.
A nice benefit to this process is that you never have to save a physical file on the server and then direct the client to that file. Everything is done in memory, so there will be no file permission problems or disk space issues to deal with.
