^ It ain't that easy for when a Wii doesn't work on a foreign TV, actually.
Bulgaria lies in Europe and uses PAL encoding (the same type UK TVs would use), so yeah, your Wii should work fine on a typical modern Bulgarian TV. There's more to it than that, however. See this.
Bulgaria is converting to a different type of broadcasting in 2013. I'm not sure if that'l affect ya in any way; I haven't read up on broadcasting systems in a long while.