Aegisub is a free, cross-platform open source tool for creating and modifying subtitles. Aegisub makes it quick and easy to time subtitles to audio, and features many powerful tools for styling them, including a built-in real-time video preview.
What's new in Aegisub
Update Spanish, Ukrainian, Hungarian and Finnish translations
Skip writing the Aegisub project stuff when exporting to ASS
Fix some ugliness in the OS X icon
Update the selection and scroll position after opening subtitles from video
Fix crash on a certain kind of malformed shift times history file
Don't set the YCbCr header field to "None" when resampling resolution without changing colors