What is new in Ado.net 2.0

Managed Providers
Server Enumeration
Asynchronous Processing
Multiple Active Result Sets (MARS)
Bulk Copy Operations
New SQL Server Max Data Types
SQL Server User-Defined Types
SQL Server Notifications
Transactions with SQL Server Snapshot Isolation
Database Mirroring in SQL Server 2005
Provider Statistics
Change Password in SQL Server 2005
Batch Processing
Tracing
Partial Trust
Connection Pooling Control
SQL Server XML Data Type Support
Integration with System.Transactions and Promotable Transactions Optimization for SQL Server 2005

Disconnected Classes
DataSet Enhancements
Binary Serialization for the DataSet
DataTable as a Stand-Alone Object
Create a DataTable from a DataView
Schema Inference Engine Enhancements
Namespace-Qualified Tables
New DataTable Loading Capabilities
Row State Control
Enhanced Support for Custom Defined Types
XML/XSD Enhancements
DataRow Enhancements
Change Position of Column in DataTable
DataView Performance Improvements
DataColumn Expressions
Schema Serialization for Typed DataSet
Provider-Independent APIs
NET Data Provider Enumeration
Provider Independent API
Schema Discovery

for more details please refer to http://msdn2.microsoft.com/en-us/library/ex6y04yf(VS.80).aspx