Convert language of subtitle files

[Eagle1111]

is it possible to convert for example a sub file that is in italian to english?

[solarfox]

Depends on how good a translation you want, and how much effort you're willing to put into it.

If you've already ripped the subtitles with Subrip (or similar) into a text-based subtitle file format, you could open it in a text editor, feed the Italian subtitles to Babelfish one line at a time, and cut-and-paste the translations back over the original Italian text. You could also e-mail the text file to an Italian-speaking friend who could translate the lines for you, which would give you a more "natural" translation.