Sub2DivX

Sub2Divx is a video muxing utility for Windows. The application allows you to hardcode a subtitle file onto a divx file video.

You can do this by adding an AVI file to the application and having its subtitle in the same folder with the same name minus the extension, which has to be srt. If you don't have the subtitle in the same directory, you can simply load it from the File menu. Once the video file and its subtitle are loaded, the Sub2Divx will automatically fit the subtitle in the screen and give you a preview of where the subtitle will be. The application supports several subtitles to be muxed into the video file. It is up to your player to recognize them once the application is done with the video file. To start the muxing process, just click on the Create divx file button. The process is no longer than re-encoding the video and the subtitle will be hardcoded into the file, so you won't have to worry about .srt files anymore.
Still the program has its disadvantages. Apparently it uses DOS components to create the divx files and add subtitles and the one component that it uses to create the files limits the output resolution to 720x480. That is not a bad resolution, but if you want to go higher, you will have to find another application. Also, you need to download a separate pack of application just to make this app work.