If you don't see HTML Spell Checker in Tools menu after the install, try the folllwing:
1. Make sure you are running RTM version of VS, not Release Candidate. Version should be 50727.42.
2. Open command line, go to Program Files\HTML Spell Checker Add-In and run
Spell checker is 100% native C++, so it does not depend on the .NET Framework installed. It does depend on version of the ATL and C++ Runtime libraries installed. You may want to log on as Administrator before installing the component since COM registration requires modifying entries under HKEY_CLASSES_ROOT.
Gory details of the registration:
when component is registered, it should show up in the registry under HKEY_CURRENT_USER\Software\Microsoft\Visual Studio\8.0\Addins. There should be a few settings there and class name HTMLSpellChecker.Connect.1 which, it turn, should appear under HKEY_CLASSES_ROOT\HTMLSpellChecker.Connect.1 and HTMLSpellChecker.Connect. The latter contains a GUID that should be present under HKEY_CLASSES_ROOT\CLSID and contain reference to the component dll.