Arcpy Improvements in 10.1

Arc Python in ArcGIS 10.1

1. Site package that adds ArcGIS functionality to Python
2. Access to rich suite of geoprocessing tools
3. Functions, classes and modules
4. Helper functions like ListFeatureClasses, Describe
5. Classes that can be used to create complex objects like Spatial Reference, Field Map
6. Modules that provide specialized functionality like Mapping,SpatialAnalyst, NetworkAnalyst, DataAccess

Complete Introduction to Python concepts for beginners is available here

ArcPython a complete Overview

ArcGIS + Python = ArcPython

For more info and advance Concepts use the folowing references: 

resources.ArcGIS.com

arcpy.wordpress.com

GIS Stack Exchange, Stack Overflow

Python References,Python Scripting for ArcGIS

GIS Tutorial for Python Scripting by Allen (Esri Press)

Learning Python by Lutz - The Python Standard Library

python.org

http://www.esri.com/training