as is my wont, I followed up on jheem's post and found this:
Till and until are generally interchangeable in both writing and speech, though as the first word in a sentence until is usually preferred: Until you get that paper written, don't even think about going to the movies.·Till is actually the older word, with until having been formed by the addition to it of the prefix un-, meaning "up to." In the 18th century the spelling 'till became fashionable, as if till were a shortened form of until. Although 'till is now nonstandard, 'til is sometimes used in this way and is considered acceptable, though it is etymologically incorrect. [EA]

having read that usage note from AHD4, I have no further questions until/till/'til further notice.

oh, BTW, the Old English word for this was til, and the Old English word for the cash drawer was tille. till and till are separate words. then there is till (cultivate) and till (glacial drift).