I've been using Test::Spellunker for a few weeks now to check pod spelling, and have been pleased with the results.
It provides a similar API to Test::Spelling, but rather than shelling out to the first spell checker it can find on the system, does a pure Perl spell check. This means you get more consistent results across different systems, including Win32.
Initial loading of the bundled dictionary is noticeable (about 1.5 sec on this old netbook), but once it gets going, testing each pod file is very fast.
Documentation is a little patchy, but it's pretty easy to use anyway so that's not a big problem.