Kernel release status
The current 2.6 prepatch remains 2.6.19-rc5; no prepatches have been
released in the last week. Enough patches have found their way into the
mainline git repository that a 2.6.19-rc6 release will probably happen
before this kernel cycle runs its course.
The current -mm tree is 2.6.19-rc5-mm2. Recent changes to -mm include the fault injection capability (see below), file-based capabilities, and a backport of the ext3 reservation code to ext2.
For 2.6.16 users, Adrian Bunk has released 2.6.16.32 with a number of fixes.