i second andrew f... and if you have a nikon or canon (digital or more modern film camera) the yongnuo will be able to connect as a regular flash (although ttle is possible with them now, they are a bit more expensive)... Also for the price of a nikon sb-900 at the time i bought a whole lighting set up including 3 yongnuo flashes, stands, brackets, umbrellas, wireless triggers, which i can use with most any film camera equipped with a pc sync cord to one flash (and optical slave triggering on the remaining 2).
If you do go this route, i recommend buying from amazon, given they're overly generous return policies, and therefore (i believe) better quality control of yongnuo products bought through them.