Where can I find Chovoth haLevavoth in Arabic?
Hovos HaLevavos / Kitab ul-Hidayah ila Fara'idh il-Qulub, as edited by the scholoar A S Yahuda, is available here:
A S Yahuda's edition is in Arabic script. Before that edition, the book was usually (or, I think, always) copied and read in Hebrew script. You can buy an edition in that format, as edited by Rabbi Kafih, and including a translation by Rabbi Kafih into Hebrew:
Nezah Yisra'el of Qiryat Ono, Israel sells the R' Yoseph Qafih (parallel Hebrew-Arabic) edition of Hovot HaLevavot.
I recently heard in a sh'iur that the Qafih translation from the original Arabic is far more accurate than that of R' Yehudah Tibbon (the presently more common translation). I have the Feldheim, "Lev Tov", and Qafih editions at home and often cross-reference the Qafih edition as it includes excellent footnotes where R' Qafih disagrees with R' Tibbon's translation.