Kaleidoscope - LLVM Tutorial [0] is an excellent resource with code samples in C++ and OCaml.
But if you use the OCaml version with a recent version of OCaml, you'll run into a few issues. I sent in a patch with a few simple updates to the path mailing list earlier this year, but last I checked it wasn't merged.
Patch is here (it's a text file, despite the "bin" extension):
http://permalink.gmane.org/gmane.comp.compilers.llvm.cvs/183...
I also pasted the patch here: