Possible Duplicate:
UK English: Is "dived" a valid word?
Spelt and Spelled
“Dreamed” vs. “dreamt”, “leaped” vs. “leapt”, “lighted” vs. “lit”
Evolution of irregular verbs over the last century
Origin of different past tenses for verbs with the same endings?
What's the difference between 'dived' and 'dove' as the past tense of 'to dive'? 'Spelled' and 'spelt' (to spell)? There are others which are similar. Is one form British usage?