So my problem with installing WordPress (2.5.1 and 2.6.1) was a blank screen at the point where the install was running in /wp-admin/install.php.
I was able to create the config.php using the web interface, however at the next step of actually installing WordPress it failed with no output to the screen and no error message in the server logs. It did not even get to the point of creating the database tables in the MySQL database.
I found nothing that worked online about this despite many suggestions, but I happened on a fix pretty much accidentally.
The fix was to add the following line to the .htaccess file in the root directory of the server.
php_value zend.ze1_compatibility_mode "0"
Do I know why it worked? No.
It was a setting I had to change for another application (MediaWiki), and it had the added benefit of fixing me up (Though it still took a little bit of time to realize that was indeed the fix)
Just throwing this out there for those that may be encountering the same thing. Hope it helps even one... Cheers.