Mono 2.0 Has Been Released

Mono 2.0 is a portable and open source implementation of the .NET framework for Unix, Windows, MacOS and other operating systems.

Some Details:

Microsoft Compatible APIs
ADO.NET 2.0 API for accessing databases.
ASP.NET 2.0 API for developing Web-based applications.
Windows.Forms 2.0 API to create desktop applications.
System.XML 2.0: An API to manipulate XML documents.
System.Core: Provides support for the Language Integrated Query (LINQ).
System.Xml.Linq: Provides a LINQ provider for XML.
System.Drawing 2.0 API: A portable graphics rendering API.

Mono APIs
Gtk# 2.12: A binding to the Gtk+ 2.12 and GNOME libraries for creating desktop applications on Linux, Windows and MacOS X.
Mono.Cecil: A library to manipulate ECMA CLI files (the native format used for executables and libraries).
Mono.Cairo: A binding to the Cairo Graphics library to produce 2D graphics and render them into a variety of forms (images, windows, postscript and PDF).
Mono’s SQLite support: a library to create and consume databases created with SQLite.
Mono.Posix: a library to access Linux and Unix specific functionality from your managed application. With both a low-level interface as well as higher level interfaces.

Download Mono 2.0 here: http://www.go-mono.com/mono-downloads/download.html