If you haven’t heard of it, Hunspell is the open source spell checking engine used in OpenOffice. Having used it successfully in personal projects over some years now, I’ve written (or rather, re-written) a simple wrapper class. In doing it, my aim was twofold: to properly support dictionaries with foreign code pages (most standard Hunspell dictionaries not being Unicode), and to work seamlessly between Delphi 2006/7 and Unicode Delphis. You can download the result here – the ZIP includes a demo together with a prebuilt Hunspell DLL, compiled in VC++ 2008 Express using v1.2.8 of the Hunspell sources.
For wont of consistency with the other code I’ve put up, I’ve given my wrapper an MPL licence, though anyone interested can basically do what they want with it so long as they don’t pretend the original code was their own. Hunspell itself is LGPL though, and the licence on common dictionaries can vary, so you might want to check things out yourself before deciding to use Hunspell for any serious development.