In this 2001's week PS2 saw the Onimusha release, which caused the almost double hardware sales in Japan. Since PS3 has no releases this week, expect PS2 to outsell PS3 by a large margin. Next week there's DMC4. Will it make things even? (I doubt it, since it's multi).
I think this week maybe will be the start of PS2's sales take off, with PS3 catching it up again only in the GTAIV release week (and I mean weekly sales, not year to date).
We could always use some graph-love:
http://spreadsheets.google.com/pub?key=pcWh4PBsQcfbi96R1gtPdGw