how can I use gd, aspell and gdbm?

Would you like to tell me how can I use GD lib? I run the ./configure --with-gd=/usr/lib --other... I have found that the libgd.so.1 is /usr/lib, but the configure script fails, and say can't find libgd.* in /usr/lib. I also want to use aspell, but the configure script say it can't find aspell header *.h files, does it mean that I must download the source. when try to configure with gdbm.. the script is also reported with "can't found.... " error. Anyone can help me? If I have to download some library first, where can I find it? Lastly, in my linux box, I compile PHP4.03 with apache as a module, (I have succeed the compilation before, with only a few configure option) but I can't find php.ini. Why, how can I configure php? Thanks!