Following are the feature enhancements of the AutoCAD Civil 3D 2008. And the new features - Plans production, someone has share the demonstration in Youtude, Autodesk blogger Anthony discuss the features here!

Data Interoperability and Migration

• LandXML 1.1 support of survey data and corridor model
• Open/export and “underlay” MicroStation® DGN format drawings
• Publish Civil 3D model for use in GIS (SDF)
• Export Civil 3D surface model as grid (DEM)
• Import image and surface from Google Earthâ„¢ mapping interface
• Export model to Google Earth
• Export Civil 3D model intelligence to DWFâ„¢ files

General Productivity and Usability

• Simplified and consistent menu structure
• Creation of AutoCAD primitives from surface models
• Wizards to help users with more complex tasks
• Interactively edit alignments/profiles graphically and numerically

Pipes

• Drafting enhancements to better support annotation and display of multisegment (no structures) pipe networks
• New pipe and structure tables
• Improved sharing and access to pipe/structure part catalogs

Alignments and Profiles

• Enhanced alignment and profile layout options
• Option to specify “no site” for alignments
• Plot vertical curve values onto horizontal alignment
• Create labels that reference multiple alignments
• Create lines, curves, and parabolic arcs using “Best Fit” layout

Corridor Modeling

• Improved corridor interaction, including creation of corridor regions, streamlined definition of targets and frequencies, and more
• Interactive generation of surface boundary
• Direct rendering of corridor model based on assembly links
• Extensive performance improvements
• New subassemblies

Grading

• Broad set of tools for creating and modifying 3D geometry (feature lines, 3D plines, 2D plines, and lot lines)
• Calculation of feature line statistics such as linear total
• Usability enhancements to streamline creation of grading features

Survey

• New, intuitive utilities to help surveyors create base geometry faster
• Third-party applications from equipment manufacturers to enable
• Movement of field-captured data into AutoCAD Civil 3D
• Movement of design model into field for machine control-based construction

Production Drafting

• Improvements to help address global drafting standards
• Enhancements to profile and section plotting and annotation
• Grading feature line label improvements
• New contour label creation interface

Plans Production

• Automated generation of roadway plan, profile, and plan/profile sheets. This new functionality greatly streamlines the process of generating alignment-based submittal sheets.
• Changes in design model result in updated roadway sheets.
• Plans Production wizard integrated with AutoCAD Sheet Set Manager for automated plotting of sheet sets.
• Plans Production Wizard integrated with Autodesk Vault.
• Generation of Split Profile views that remain dynamic to the model

Multiuser Project Environment

• Multiuser access to AutoCAD Civil 3D model for design, analysis, and drafting using either Autodesk® Vault or data shortcuts
• Robust data management for all project drawings and documents
• Generation of corridor sections through AutoCAD external reference (xrefs)
• Additional administration flexibility