I’m reading Discover FORTH: Learning and Programming the FORTH Language and I have a growing interest in the programming language Forth. Here are a few resources:

• forth-standard.org
• Forth Vs Lisp
• Konilo
• /faq
• TclForth – A multi-platform Forth based on Tcl/Tk

And some other books on Forth:

• Zen and the Forth Language: EFORTH for the MSP430 from Texas Instruments
• Thinking Forth

And there are a heap of Forth books by Juergen Pintaske.