Long Time No See: The direct translation would be 好久不見. This is a valid and even very common phrase. It's pronounced more or less as "hao jiu boo jian". Keep in mind though, that this is...
In Japanese you say 「お久しぶりです。(O-hi-sa-si-bu-ri-de-su)」 if you'd like to be polite.To be more friendly, it would be better to say 「久しぶり。(Hi-sa-si-bu-ri)」