Something I can answer! 8-) I'm actually working on a project that uses this, right now.
Do not use Acrobat Reader as any sort of server application. It has a User Interface that will pop up on a screen that doesn't exist, at an unexpected time and freeze your app, waiting for a click that will never happen.
Use Ghostscript. Ghostscript is free, Open Source and will work perfectly for what you want. Out-of-the-box it consists of a DLL and a command line inhterface, however there is an API and a ton of different interfaces including .Net, and versions for both Windows and Linux.
On a more "overview" type of note, the reason you can drag a PDF into a printer on your workstation is because Acrobat Reader contains the code and hooks to allow this. Windows doesn't actually contain native functionality to print PDFs.