I have seen several attempts at translating the Ring Verse into Sindarin (some much better than others). I'll give you links to two attempts. The first is by Ryszard Derdzinski and the second by Taramiluiel (Personally I like Mr. Derdzinaki's translation the most). You can also find a Quenya version on his site. There is also a Black Speech translation (well reconstructed Black Speech anyway) by David Salo on Pg. 17 of the Fellowship of the Ring Complete Recordings Annotated Score (go to the third link for the download)
1.
http://www.elvish.org/gwaith/ringpoem.htm
2.
http://www.cox-internet.com/taramiluiel/ring_verse.htm
3.
http://www.lordoftherings-soundtrack.co ... plete.html
Enjoy!