Download the latest version of Silverlight 2 RTW (2.0.31005.0) at http://www.microsoft.com/silverlight/ You can find additional detail on Silverlight and what's new in Silverlight 2 from Tim Heuer's blog and debugging Silverlight applications on Mac from Peter Laudati's blog.

Also, check out the supported browser versions and system requirements below.

Compatible Operating Systems and Browsers

Operating System Windows Internet Explorer 7 Internet Explorer 6 Firefox 1.5, 2, 3 Safari
Windows Vista Yes - Yes -
Windows XP SP2 Yes Yes Yes -
Windows 2000 - Yes** - -
Windows Server 2003 (excluding IA-64) Yes Yes Yes -
Mac OS 10.4.8+ (PowerPC) - - Yes* Yes*
Mac OS 10.4.8+ (Intel-based) - - Yes Yes

* Silverlight 1.0 Only ; ** Silverlight 2 Only
Minimal Requirements

Components Requirement
Personal Computer running Windows X86 or x64 500-megahertz (MHz) or higher processor with 128-megabytes (MB) of RAM
Mac OS 10.4.8+ (PowerPC) PowerPC G4 800-MHz or higher processor with 128-MB of RAM
Mac OS 10.4.8+ (Intel-based) Intel Core Duo 1.83-gigahertz (GHz) or higher processor with 128-MB of RAM

RECOMMENDED: Use Silverlight in the 32-bit Internet Explorer process on x64 systems. Most browser plug-ins (including Silverlight, Flash, Java and almost all ActiveX controls) only work in 32-bit browsers currently.