In the most recent issue of EGM (Electronic Gaming Monthly), there was a small note about Ninja Gaiden Black being ported to the PS3 next spring.
There has not been any offical confirmation from Tecmo or Team Ninja.
Team Ninja is perfectly capable of bringing this rumor to realisation and have Ninja Gaiden become multiplatform.
There were statements earlier this year from Tomonobu Itagaki, head of Team Ninja stating that he would wait and see what Sony will offer before he makes any decisions.
Knowing Team Ninja and their hunger for incredible graphics they must have been impressed with the showing of the PS3 at E3 last month.