For those will problems installing on Win32 with IIS:

Symptom: browser just hangs when calling pspell function. Running PHP.exe from command line causes pspell to claim that there is a corrupt file. Running Aspell works just fine on the command line.

You need new data files: 

You can download and get more information about it here:
http://wiki.wordpress.org/SpellCheck

Just replace the data directory in C:\Programs Files\Aspell\ with the new data directory you downloaded.

No more problems.