This wiki page will describe available emulators and simulators for the various mobile devices.  For each we'll highlight to pro/cons of the approach, and links to installations and setup options.

iOS

• http://developer.apple.com/

Android

• http://developer.android.com/sdk/index.html

BlackBerry

• http://us.blackberry.com/developers/tablet/webworks.jsp
• http://code.google.com/p/webdriver-blackberry/
• http://us.blackberry.com/developers/javaappdev/javaplugin.jsp
• http://www.ruby-lang.org/en/downloads/
• http://rake.rubyforge.org/

Windows Phone

• http://create.msdn.com/en-US/education/basics/developer_resources

3rd Party