And by Mozilla/Gecko/Firefox plugin, I don’t mean extension, but an honest-to-goodness, C++ application embedded in the web browser.

First off, let me tell you, it’s a huge pain in da patookis. Making a very simple plugin isn’t that big of a deal. Even scriptable from the original HTML page. Oh wait, but you want a user interface? Oh, now we’ll have to haggle.

I’m very glad now that extensions and wonderful there-is-only-xul have been developed. Not to mention JavaScript. Kids (by kids, I mean programmers) today have no idea how easy they have it developing pretty slick, cross-platform tools, built on the backs of Netscape.

Here are some great resources for XPCom, the modular design that Firefox and it’s bretheren are built on which allows plug-ins and add-ons to the browser without having to recompile the browser.

• XPCom tutorial example
• Building the GeckoSDK on Mac OS X
• IBM Developer Works, XPCom Overview
• Example: MPlayer Plug-in