The instalation section indicates;
Installation
If you have the libraries needed add the --with-pspell[=dir] option when compiling PHP. 

Note to Win32 Users: In order for this extension to work, there are DLL files that must be available to the Windows system PATH. See the FAQ titled "How do I add my PHP directory to the PATH on Windows" for information on how to do this. Although copying DLL files from the PHP folder into the Windows system directory also works (because the system directory is by default in the systems PATH), it is not recommended. This extension requires the following files to be in the PATH: aspell-15.dll from the bin folder of the aspell installation. 

Do you not feel that referencing the DLLs in the instalation secion is sufficient? While the lines are blurred on windows, adding a DLL counts as an instalation step, not runtime configuration. 

Win32 support is available only in PHP 4.3.3 and later versions. Also, at least aspell version 0.50 is required.

>>Do you not feel that referencing the DLLs in the instalation secion is sufficient?

I had assumed the DLLs being referred to were the aspell DLLs, not the extension DLLs in the runtime configuration.  Indeed, the aspell DLLs need to be in the PATH as mentioned in the Win32 note you quoted.  But the statement "This extension has no configuration directives defined in php.ini" is not a true statement.  For Windows users there is indeed a runtime configuration directive that needs to be uncommented.  I think the extra note to Windows users would be very beneficial.

>>While the lines are blurred on windows, adding a DLL counts
as an instalation step, not runtime configuration.

I agree, but once the PATH has been set for a Windows installation, the php_*.dll files merely need to be uncommented in the php.ini and the HTTP server restarted.  We are no longer adding DLLs at this point, really.  They are already "there" in the extensions directory and they will now be dynamically loaded upon server start.  What we are doing is making adjustments to the php.ini (runtime configuration) file.  The documentation clearly states that "This extension has no configuration directives defined in php.ini."  I think this causes confusion.

Thanks for listening,
Todd

I'm hijacking this bug report because the problem is larger than pspell.

Currently there is not a clearly defined method for documenting extension specific Windows installation information. First, a few related entities that are used in the docs (count):

* &ext.windows.path.dll; (7)
  This talks about path and currently is only used when external 
  libraries are required (Example: LDAP needing libeay32.dll).

* &no.config; (63)
  This states that no configuration options exist for it. I don't
  feel this should be changed to worry about the extension ini
  option.

* &pecl.windows.download; (21)
  Links to where a person can download PECL dll files.

We don't always mention the php_* file (like php_pspell.dll) when we should. However, we can't say they are required because although our compiled Windows binaries may not have it... others may. But still, mentioning them is a good idea. They will exist in either the main distribution, and/or in the installer, and/or in the separate PECL binaries download, and/or at the above site.

What we need is a clearly defined structure for this topic... one that's generic and flexible enough to meet the needs of every extension, both bundled and not. Someone feel free to look at a few different ones (like ref.mysql, ref.crack, ref.mailparse, and ref.pspell) and come up with something.

Please track these long-term decisions in RFC.