The current development kernel is 2.6.34-rc6, released on April 29. This
prepatch includes a lot of fixes, supplemented by the VMware balloon driver
(discussed briefly here in
early April) and the ipeth
driver which facilitates USB tethering to iPhones. The short-form
changelog is in the announcement, or see the
full changelog for the details.
Stable updates have been nonexistent over the last week.