Gnome Subtitles is a free, open-source subtitle editor for the GNOME desktop environment. It supports the most popular subtitle formats such as SRT, SSA, SUB and more. It has a simple and intuitive interface that allows users to easily create, edit, and save subtitles. Its features include support for different encodings, auto-complete, drag and drop, spell-checking, and spell-checking as you type. It also includes a search feature to quickly find any phrase in the subtitle file. In addition, Gnome Subtitles can be used to convert subtitle files between different formats.
The discontinued official website is no longer available.
Suspended the latest version is 3.0.0.4 (09/23/2005, 650Ko, with its Delphi source code): it can still be downloaded from SourceForge.
It works, it's easy to use, it has a good wave screen. Unfortunately it runs on Windows only. Many of the others listed here don't work, or are clunky. Aegisub is great, but it's too complex and difficult to use for what most people want to do.