I've noticed that there is a lot of inconsistancy between American and British English. I've seen quite a few pages that use British spellings or terms. This isn't surprising, since some of our most prolific contributors are from the land of Monty Python. Since The Simpsons is an American show, we should try to stick with American English, and try to make things consistant throughout the site.
I understand that it's not easy - I'm Canadian, so it took me a while to remember to spell words like colour as color and defence as defense (and I do still forget occasionally). But, if you start watching for those things, it becomes easier.
I'm not saying anyone should comb through the site and correct things - just keep it in mind, because it will help cut down on future uses, and wil improve the site as a whole..