  We study a brane-antibrane system and a non-BPS D-brane in SU(2) WZW model.
We first discuss the tachyon condensation using the vertex operator formalism
and find the generation of codimension two D-branes after the condensation. Our
result is consistent with the recent interpretation that a D2-brane is a bound
state of D0-branes. Then we investigate the world volume effective theory on a
non-BPS D-brane. It becomes a field theory on the ``fuzzy sphere'' when the
level is sent to infinity. The most interesting feature is that there exist the
noncommutative tachyonic solitons and we can identify them with D0-branes. We
also discuss the brane-antibrane system from the world volume point of view and
comment on the relation to the noncommutative version of the index theorem.
