Valkyria Chronicles | PS3Blog.net
This is a Japanese strategy RPG developed by Sega exclusively for PS3. Unfortunately, Disgaea 3, which was the other big strategy JRPG for PS3 was pushed back to 2009.
This is out in Japan and headed to the West in November. There are also trailers on the Japanese PSN if you have a Japanese account setup. These videos show more cut scene footage than gameplay but the art style looks very nice.