As far as learning how to create samples, it\'s just like \"How do I get to Carnagie Hall?\"
Practice! This is an area that you can only learn by listening to your mistakes.
But there are also some wonderful recording forums at MusicPlayer.com. They can teach you a LOT about recording technique, mike placement, etc. Folks like Ed Cherney, George Massenburg and Roger Nichols are moderators. Great stuff!