I don’t really know how in the heck Aegisub works, but it does. I also don’t know what else it’s capable of doing, but I use it for adding subtitles to videos edited in Virtualdub.
You’ll need Virtualdub, Aegisub, and VSFilter (VSFilter is the plugin that makes it all work). So, get Virtualdub, then go grab Aegisub and don’t forget that pesky plugin, VSFilter. I’d get the VS filter without the installer, unzip it, drag the VSFilter.dll to your Virtualdub plugins folder, rename it VSFilter.vdf, and you’re good to go.
Now, next time you have a video you want to add subtitles to, just open Aegisub, drag the video onto the interface, add the text where you want it (I’m not going to tell you how to use it; you’ll have to figure it out), and save it. Typically I use the .ass extension (really).
Then open your video in Virtualdub, go to Video –> Filters –> Add –> TextSub (the new plugin), browse to your file (with the .ass extension), open it, and . . . . you’re done! Of course you have to save your new video but you should now have subtitles.
If you’re interested in using a simple script for fading text, check out this link.
If you want something easier than all this for adding subtitles to your videos, I’d suggest buying some commercial software like Pinnacle or Sony Vegas. But I’m not suggesting that anyone really buy those packages. I think you’d be much better off figuring this stuff out on your own!
For a bit more assistance figuring this out, check out this informative Youtube video (just remember that Aegisub now comes with its own installer - you don’t have to download all the separate .dll files like it says in the video).