after untaring the download I ran
/usr/local/bin/phpize: aclocal: not found
I have autoconf, automake, gnu make and gcc 3.3.2
I had the same problem ('aclocal not found') and was able to get around it by reinstalling autoconf, automake, and libtool. I can't say that I completely understand exactly which piece fixed the problem, but you might check to make sure you have an aclocal in your path. If not, take a stab at getting it installed.
I found that the install was a little touchy on exactly which version of libtool, etc I had, but with a little puttering, got it compiled and running.
libtool update did it.
I have a similar problem (see other phpize thread) however updating to the latest versions of everything hasn't solved the problem.