I use the Linksys security cameras but they only stream asf files. I am sick of depending on IE for functionality so this plug in for Firefox works great for me!!
Microsoft Releases Media Player Plugin for Firefox: "The plugin is easy enough to get: navigating to a web page that has the embedded WMP ActiveX control within a Firefox browser, the new plugin will automatically be grabbed for your instillation, though you may need to restart your Firefox browser."
You can get the Windows Media Player Firefox plugin here.