Weekly Jump Issue #8 Goes on 'sale' to the Japanese public January 21st. But as you well know, that issue will likely leak to the internets earlier then the sale date. Mass calamity withstanding, you can likely expect to be reading the full chapter 'Friday January 18th or Saturday the 19th' 2008.
You can expect the spoilers to leak anywhere between Monday the 14th & Wednesday the 16th of January.