However, help is at hand, Reece from Facebook support, told me about a little known feature of Firefox – auto spell check.
It doesn’t come pre-installed – you need to go to Tools | Add-ons and search for SpellCheck – then install the language you want.
Once installed – the browser restarts and now your facebook email field does a nice red underline when you’ve spelt (spelled) something wrong…. ;o). Problem solved.
UPDATE – 13 JAN 2010
UPDATE – 9 Nov 2010
New instructions for current Firefox