Similar to how Nintendo picked up publishing rights to Dragon Quest IX or how Nintendo of Europe occasionally releases Atlus games, Microsoft is handling PopCap Arcade in Japan.
The Xbox Live Arcade compilation was announced as a first party title and slated for June 3. Microsoft Japan’s version of PopCap Arcade is actually PopCap Arcade Volume One and PopCap Arcade Volume Two on a single disc. Bejeweled 2, Zuma, Feeding Frenzy and Astropop from Volume One plus Heavy Weapon, Feeding Frenzy 2, and Peggle from Volume Two are sold in a single package for 3,990 yen ($43).
Since both games are already in North America there’s no reason to import PopCap Arcade. However, it’s always interesting to see which Western games Microsoft picks up and brings to Japan. Their West to East Xbox 360 localization list includes Overlord, Borderlands 2, and this.