I used the following steps to upload, untar and compile php on dreamhost.com
The "$" sign indicates an actual command line syntax.  Don't use the "$" sign
obviously.

I am NOT an expert but this is what worked for me.  If you see anything wrong
here please contact me at kelly@kellybreed.com.
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1)  Download tar.gz file for php4.3 (http://www.php.net/downloads.php) and put into your home directory on Dreamhost, not the directory your web pages are served from.  It will be one level up from the www.yourdomainnamehere.com directory.

2)  Unzip and untar the file:

$  gzip -d php-4.3.0.tar.gz
$  tar -xf php-4.3.0.tar
    
This will leave you with a directory called php-4.3.0

3)  cd into the resulting directory and run the following three commands:

4)  Note that the following command is all one line and wherever you see "walkinth" you should replace it with your own home directory name:

$ './configure' '--with-mysql' '--enable-force-cgi-redirect' '--with-config-file-path=/home/walkinth/local/etc/' '--enable-trans-sid' '--enable-ftp' '--with-xml' '--with-zlib' '--prefix=/home/walkinth/local' '--without-pear' '--with-gd' '--with-jpeg-dir=/usr/lib'

5)  $ make

6)  $ make install prefix=$HOME

7)  cp the resulting binary (should be located in your home directory at bin/php) into a cgi-bin in the root www directory (the www.yourdomainname.com directory).  You'll probably have to create the cgi-bin within the root www directory yourself using this command: mkdir cgi-bin

8)  rename that php binary to php.cgi

9)  also cp the file php.ini-recommended to the cgi-bin and change the name to php.ini

10)  be sure that your cgi-bin and the scripts in it have permissions set to 0755 using this command: chmod -R 0755 cgi-bin

11) in the root www directory create a file name .htaccess and put the following two lines in it:

AddHandler php-cgi .php 
Action php-cgi /cgi-bin/php.cgi

This will cause all scripts that you have named with the suffix .php to be directed to your newly made cgi version of php rather than the default system one.

12)  set the permissions on the .htaccess file as such: chmod 0644 .htaccess
  
13) test it by creating a file in the root www directory called test.php and putting this into it:
<?php
phpinfo();
?>

When you pull up that page via your web browser you should get all the info associated with your newly installed version of php.