The (approximate) date is set and LLVM will be imported into FreeBSD as an alternative base compiler, with the general intention of it being the official base compiler!
There was much somewhat heated discussion about LLVM in FreeBSD but there are so many good things that will come from it that it would simply be unfortunate to miss them. In addition to these there are some more interesting stuff that can be done once LLVM is imported, like JIT-compiling IPFW firwall rulesets and BPF code with LLVM.
With the compiler, the rest of the toolchain is also under consideration.
Good news and good times...
Almost offtopic: there's a list of third-party contributed software in FreeBSD now.