Maybe a very basic one, like the kind Kabuto used in Part I against the Anbu in the Chuunin Arena. I can't see him having a higher ranked one than that though.
He probably does, being that he was the Hokage and was knowledgeable in quite a wide variety of jutsu. I am uncertain of his capabilities with it though, Space/Time Jutsu &Sealing Jutsu seems to be his thing, there hasn't been any --or atleast i have not seen any-- use of genjutsu in the manga by him. So he might just have a basic Hokage Level mastery of genjutsu.