Hi there Rick.
I'll let John comment on having that feature directly in the forum (I'm not sure if vbulletin has a spell check plugin or not).
However I use FireFox as my browser and when I'm typing the spell checker add-on that I use in FireFox automatically spell checks as I go. I find this feature indispensable! If a word is misspelled it gets underlined in a red-squiggly line and when I right click on it then the correction spelling will present itself. Just click on it and presto! Spell check done!