Advice: English dialects on Wikipedia: Wikipedia has millions of readers; some use American English, or British English, or International English, or any of numerous other local forms from Australian English to Canadian English. Because of this, Wikipedia has a policy of respecting articles written in whatever form of English the original author of the article used.
The guidelines are simple. For subjects exclusively related to Britain (for example, a famous British person), use British English. For something related to the United States in the same way, use American English. If it is an international topic, use whatever form of English the original author used.
In view of that, please don't change articles from one version of English to the other, even if you don't normally use the version the article is written in. Respect other people's versions of English. They in turn should respect yours. Other general guidelines on how Wikipedia articles are written can be found in the Wikipedia:Manual of Style. If you have any queries about all this, just ask anyone on Wikipedia and they will help you. Enjoy your time on the internet's fastest growing encyclopædia (or encyclopedia, if you write it that way!). Thank you.