Geoprocessing tools now execute in a background process, allowing you to continue working with the application (ArcMap, ArcCatalog, ArcScene or ArcGlobe) as the tool executes.
ArcToolbox functionality has been replaced by the Search window, the Catalog window, and the Results window. The ArcToolbox window is still available in ArcGIS 10 but the primary method for finding and running tools is with the Search window which is an index of geoprocessing tools developed at ESRI as well as your own custom tools.
A new Geoprocessing menu has been introduced to the standard toolbar. This menu contains all the options for configuring the geoprocessing system as well as six commonly used tools.
You can easily add tools to the Geoprocessing menu or any menu or toolbar to quickly access your favorite tools. You can even add your own Models and Script tools to the application user interface through this new functionality.
The Python window is where you can execute tools in command line style environment. The Python window replaces the Command Line window from previous releases. The Command Line window allowed you to run geoprocessing tools and modify geoprocessing environment setting. The Python window can be used to run tools and set environments like the Command Line did, but it also allows you to access the arcpy scripting functionality (list functions, describe data properties, cursors and more), as well as other useful functionality available in the python language.
ArcGIS installs Python version 2.6.
All geoprocessing tools, as well as a wide variety of useful functions for interrogating GIS data are available in the ArcPy site-package. A site-package is Python's term for a library that extends the Python language with additional functionality. The ArcPy site-package is how ArcGIS delivers GIS functionality to Python. The ArcPy site-package is installed with ArcGIS automatically. You can think of ArcPy as replacing arcgisscripting in your Python code.
ArcPy contains two important modules: the mapping module (arcpy.mapping) for interacting with ArcMap and creating map books, and the spatial analyst module (arcpy.sa) for performing map algebra. A third module, geostatistical analyst, contains classes for setting up complex neighborhood searches.
With ArcGIS 10, you can protect your models and scripts—your intellectual property—with a password. This prevents the recipients from editing your model and script tool while still allowing them to run it. A password-protected model or script cannot be viewed. When copying it, the password protection stays intact.
In addition, you can import your .py file into the tool (in fact, you must do this to password protect a script tool). This means you don't have to deliver a separate .py file for your script tool to work, the .py will be saved within the toolbox. Once the .py file is imported, you can export it again (as long as you know the password) in order to modify it.