There is a Wiki dedicated to the ForthLanguage: http://wiki.forthfreak.net/
Travellers from the remote ForthWiki might have a look at ForthLanguage here.
..and there is a page about RethinkingCompilerDesign which uses Forth as its starting point. --JamesCrook.
There's another Forth-related wiki, SleeplessNightWiki.
It's primarily focused on QuartusForth, but other Forthers are welcome. There's a little bit about ColorForth and other Forth systems (Enth/Flux, for example).
-- KrisJohnson