Yes, if apache was installed via the DSO method, then you can do this. look for loadmodule and addmodule statements in your httpd.conf file. If you have those then you have an apache compiled for dynamic shared modules (DSO).
Just find the apxs script in the apache bin directory and point PHP to it like this when configuring:
./configure --with-apxs=/www/bin/apxs --with-other-options
make
make install
of course, your path won't be the same as mine, but that should work.
Then php should add the loadmodule/addmodule lines for you, and put in two commented out lines that are addhandlers for php. Uncomment those lines and restart apache and you're set.