You could say that Konami has seen the light.
Boktai was an ingenious game that used real sunlight to affect how strong or weak the enemies in the game were. It did pretty well in the States, but Japanese sales weren't as good because of bad weather during the summer.
That's not stopping Konami from producing a sequel. "Continued - Bokura no Taiyou" is what the second game in the line is currently being referred to in Japan. All that's known about the game is that it's going to get a pretty big overhaul from the original, and that the sun sensor will play an even larger role than it did in the first game.
It seems likely that this game will come Stateside as well, so we'll keep our eyes peeled for Boktai II and share the details when they revealed.