First off, welcome to the 'Downs, Zeno. I hope you decide to stick around even after your question has been answered!
Actually, as Aiwendil has just beaten me to saying, The Grey Company is actually the site of a roleplaying group. Their Elvish (Occassionally referred to as "Grelvish") isn't accurate to either strain of Tolkein's. While it's very interesting, even cool, in its own right, it's not actually Quenya or Sindarin.
There was an Elvish glossary-thing published in The Lost Road volume of HOME, so that's a primary source of information on the languages.
I don't know too much about online translators, as the ones I played with seem to not be around either, but if you're interested in delving deeper into the study of the Elvish languages, here are a couple websites I can recommend, from the days when I actually had time to study fabricated languages. I used to be able to write fluently in Tengwar characters, and I was in the process of learning Sindarin...*sigh* Those were the days. Now I have a bunch of journal entries I can't even read sitting around back home. My "secret code" of Tengwar has proved to be a little too secret.
ANYWAY...
Back then,
http://www.uib.no/People/hnohf/ (EDIT:which Aiwendil has beaten me to) was (and probably still is) considered to be the leading authority on all things Elvish. I never actually used it, since most of the information is in download format, and at the time, I didn't have my own laptop, and my parents were overcautious about downloading stuff.
The Council of Elrond
http://www.councilofelrond.com/modules.php?op=modload&name=Content&file=index&act ion=ViewContent&cid=31 page offers tools for learning Sindarin or Quenya (though to use the workbooks, you'll have to be a registered member. No big deal.), translations of Elvish in the books and movies, links to more resources, and a couple forums for language discussion, it looks like. I only ever used the workbooks, and they seemed from my very unprofessional opinion to be very well thought out and put together.
I hope this helps you in some way, though it may be more than you were really looking for...and thanks for mentioning Elvish! I still think about it wistfully from time to time. Now that you've re-awakened my curiosity, I might just start studying again this winter once school calms down. Yay!