With the upcoming Atlantis release, we would like to ask for international users to help out by translating XBMC into your language or if it’s already translated, review and improve the current translation.
Deadline for submitting these translations is the 25th of october.
There are a some help on the wiki
Also there are an nice application to aid you in translation called XBMC Translator
Discuss this, ask questions and make suggestions in this forumthread.