There are at least 2 artists by this name 1) Змей is a currently on hiatus Bulgarian blues-rock trio, consisting of Rossen Nedelchev - drums; Stanislav Dombov a.k.a. "Dombi" - bass and vocals and Boyan Hristov - guitars and vocals. Their first records from 2005 are released for a free download on the website of Boyan. Some of their songs could be heard on the official myspace of the band: http://www.myspace.com/zmei3
2) Змей is a rap-artist from Каста band.