The Intel® Embedded Software Development Tool Suite for Intel® Atom™ Processor is available for free 30 day evaluation with 1 time renewal as part of the

Intel® Atom™ Processor N2800 Development Kit
Intel® Atom™ Processor D2700 Development Kit

seed program.

These development kits come with Yocto Project* 1.1 reference builds. Check it out at  

http://www.intel.com/p/en_US/embedded/designcenter/tools/seed-board-program