Recently I've decided to learn sanskrit due to being a bit put off by the translation issues of various texts I read: often the message seems to be garbled by misunderstanding or just inaccuracy of language. So by learning it, I should be able to get back to the original messages (Despite the fact that the Buddha didn't want his sutras translated into the official spiritual language of the time, they went ahead and did anyway after he passed on)
So if others are of same mind, this is what I am referencing at the moment, seems to be pretty good so far:http://www.learnsanskrit.org/grammar
a fine aspiration, but be aware of the fact that many important texts only exist in Tibetan or Chinese, and even when there is a Sanskrit version extant, it is usually much later than the Tibetan or, especially, the Chinese version. No scholar bases a reading on just Sanskrit with no reference to Tibetan and Chinese versions. So the dream that knowing sanskrit will remove all doubt about text interpretation is really just that. Having said that though, personally I give preference to scholars who know all three languages, or at least sanskrit plus one of the others, over scholars who only know either Tibetan or Chinese. Ezra Pound said "I believe in technique as a test of a man's sincerity". If one is really serious about Buddhist studies, and I mean in the sense of making it one's life endeavor, one will learn the languages, as many as possible. I remember my shock when, early in my interest of Tibetan Buddhism, I learned that monks did not routinely study sanskrit, even in the supposedly "scholarly" traditions. I was like, WTF???