Before doing anything else, get on the mailing list for documenters and translators (i.e. send mail with "subscribe" in the subject and the body to kde-i18n-doc-request@kde.org). This mailing list is being archived with the other major KDE lists at lists.kde.org. -- Second: Take a look at the list of languages and coordinators in KDE.
What follows depends on whether your language is listed on that page or not.
If your language is listed, simply write to the coordinator(s) of your language team and ask him, her, or them on how to proceed.
If your language is not listed, post a message to the mailing list if anybody is working already on your language or would be willing to join your effort.
(Note for translators in need of right-to-left support for their fonts: please contact Lars Knoll about the current status of "bidirectionality".)
(Note for all other people using non-latin characters: KDE 2 supports Unicode. I still have to find a good overview, however, as to what this means in practice. Until then, I have to refer everybody to www.unicode.org.)
If nobody else on the list replies, you will get a message from the i18n coordinator (if you don't, just wake him up;). He will probably suggest you should become the coordinator for your language and to proceed as follows...