Ghostscript.NET
The most completed managed wrapper around the Ghostscript library.
All other C# Ghostscript wrappers that you can find on the internet does not allow you to progressively render PDF page directly to the screen without exporting the page to the disk first. This wrapper does not require exporting to the disk, it can render tiles progressively from the Ghostscript interpreter. Please go to http://ghostscriptnet.codeplex.com/ for development files.