Spring.NET is an application framework focused on helping build enterprise .NET applications.
http://www.springframework.net/index.html

The iBATIS Data Mapper framework makes it easier to use a database with Java and .NET applications. iBATIS couples objects with stored procedures or SQL statements using a XML descriptor. Simplicity is the biggest advantage of the iBATIS Data Mapper over object relational mapping tools.
http://ibatis.apache.org/


NHibernate for .NET
NHibernate is a port of Hibernate Core for Java to the .NET Framework. It handles persisting plain .NET objects to and from an underlying relational database. Given an XML description of your entities and relationships, NHibernate automatically generates SQL for loading and storing the objects. Optionally, you can describe your mapping metadata with attributes in your source code.
http://www.hibernate.org/343.html


not sure if its any good
http://www.vanatec.com/en/community-support/download/start_download4