About -arch i386, sorry my English is poor, what I mean is, gprof is not working even with binaries compiled with -arch i386.

Thats still wrong:

  247:~ Zach$ gcc -pg -arch i386 foo.c -o foo
  247:~ Zach$ file foo
  foo: Mach-O executable i386
  247:~ Zach$ ./foo 
  hello
  247:~ Zach$ gprof foo
  
  
  
  call graph profile:
            The sum of self and descendents is the major sort
            for this listing.
  
            function entries:
  [rest of the output snipped, I can pastebin if you want.]

Though, you should really look at Shark (`man shark`, or Developer/Applications/Performance Tools/Shark.app), as an alternative to gprof.

However, you are right about Valgrind not working on Snow Leopard yet. I had thought it was working by now. Whoops, on my part. I edited my first post.