Copied from HCI Design's Homepage:


FreeSpell is a spell checker for any and all Windows applications.
You can use it in Microsoft Outlook, Firefox, Visual C++, and even in Windows Explorer when renaming files. In fact, anything that supports the clipboard supports FreeSpell, and all it takes is a hotkey to invoke it.
FreeSpell is based upon the Aspell engine, which means it offers the best spell checker around for people with weak spelling skills (as well for people who just need a quick proofread). FreeSpell comes with a large default dictionary and has custom dictionary support.FreeSpell is a spell checker for any and all Windows applications.  You can use it in Microsoft Outlook, Firefox, Visual C++, and even in Windows Explorer when renaming files. In fact, anything that supports the clipboard supports FreeSpell, and all it takes is a hotkey to invoke it. FreeSpell is based upon the Aspell engine, which means it offers the best spell checker around for people with weak spelling skills (as well for people who just need a quick proofread). FreeSpell comes with a large default dictionary and has custom dictionary support.

Please note the name. FreeSpell is entirely free. You and I deserve an easily accessible spellchecker for use with all applications, and that is why FreeSpell was written. This product will always be free - no expiration, no nag screens, no guilt trips. Spell checking should be built into the OS, and until it is, FreeSpell will provide it for you for free. There is, however, a deluxe version of FreeSpell which has additional features. We also make ProSpell; a version of FreeSpell which offers a fully GUI based interface. By downloading FreeSpell you also got a copy of ProSpell. You can try out both programs without obligation. Note, however, that ProSpell is not free. In order to allow full functionality you must register it.

Please note the name. FreeSpell is entirely free.
You and I deserve an easily accessible spellchecker for use with all applications, and that is why FreeSpell was written. This product will always be free - no expiration, no nag screens, no guilt trips. Spell checking should be built into the OS, and until it is, FreeSpell will provide it for you for free.
There is, however, a deluxe version of FreeSpell which has additional features.
We also make ProSpell; a version of FreeSpell which offers a fully GUI based interface. By downloading FreeSpell you also got a copy of ProSpell.
You can try out both programs without obligation.
Note, however, that ProSpell is not free.
In order to allow full functionality you must register it.