I played around with Go a bit shortly after it came out. There wasn't a profiler then; is there one now?
I use pprof package, and Google perftools.
If you use the gccgo compiler instead of the 6g compiler, you'd probably be able to use the normal GNU tools, i.e. gprof.
I haven't actually done it with gprof, but I at least know that it works for gdb.