HTC has made the Gingerbread kernel source for the EVO Shift 4G, HTC Thunderbolt, and Droid Incredible available for download on their developer center website. As always, unless you're a kernel developer or ROM chef, this won't do too much for you -- other than build anticipation for the awesome new flashables that will be coming soon for these three.
Devs, have at it. And don't be afraid to holler at us when you get something good cooked up!
Source: HTC Developer Center