Kernel release status
The current 2.6 prepatch remains 2.6.18-rc4. Linus surfaced from his vacation long enough to merge 100 or so fixes into the mainline repository, but little more than that has happened on that front.
The current -mm tree is 2.6.18-rc4-mm2. Recent changes to -mm include a kernel stack protector patch set (labeled "security placebo"), the ability to filter core dumps through a helper application, and a lot of fixes.
The current stable 2.4 kernel is 2.4.33.2, released on August 22. It contains a small number of fixes, including one for the latest SCTP vulnerability. Previously, 2.4.33.1 came out on August 19 with another pair of security fixes.
The 2.4.34 process has begun with 2.4.34-pre1, with another small
set of fixes (but see below as well).