The newest build is 0.1.3. You can download it here.
Chimera has complete build instructions on mozilla's Web pages (under the code name ChimChim). You can find those instructions here. Be aware that the downloadable build listed above contains numerous patches to Mozilla that have not yet been accepted, so any builds that you do will not be as stable or as performant as the downloadable build above.
If you have questions about building, use the chimera mailing list or hop on to #mozilla, and someone can help you out.