[link|http://www.angelfire.com/tx4/cus/shapes/brain.html|brainf*ck] does it with a mere 6 instructions - and two of those are unnecessary since they have to do with I/O. Even shorter are [link|http://www.angelfire.com/tx4/cus/combinator/birds.html|SK Combinators] which achieve Turing completeness with a mere two combinators:
   K such that:  Kab = a\n   S such that:  Sabc = ac(bc)

Or you can even get down to [link|http://www.cs.uu.nl/people/jeroen/article/combinat/index.html|one combinator].

Not that you really want to program in these turing complete languages. :-)