Okay I'll start with my suggestions, add yours:
- Update the official PS2 site with more info about the game.
- Remake the Teaser for the Trailer into a TV spot.
- Have The9 and Pro7 work on translating it into different languages.
- Launch it on TV.
- Prepare the Launch Trailer, I advise old Battlefield-style engine-based trailer with script.
- Rent some billboards worldwide with THIS image and the address of the official site at the bottom.
- Have some retail boxed version of the game by launch like NFSW did.
- Sell merch (e.g. dogtags, jerseys)
- Live-action shorts released once a week until Launch a la Halo.
- Tatwi's secret thingamajig
EDIT: This includes both close and long-term plan suggestions.