I don’t think that Spelling Bees are particularly healthy or educational for kids. However, there is a brand-new free online version of one called Big IQ Bee that I think could be somewhat useful to English Language Learners.
Students have to register, which is very easy to do. Then they determine their difficulty level. Words are spoken in a computer-generated voice, and are also used in a sentence. Players then spell the word.
Players are rated in some kind of leader board, but they’re not actually playing against others in real-time.
I can certainly see my students liking to play it now and then though, for spelling skills, the game Spelling City is the best one out there. I rated it number two on The Best Online Learning Games — 2008.
I’m adding the link to my website under Spelling.