The plugin websend, linked above, is probably the easiest way to do this, But the better way is to make a custom .jar and link it, using php to your website, which must be php enabled, in other words the website cannot be like an enjin site... etc. I think to use that plugin you still may need to do some php stuff on the website end. but i am not sure. Hope i was able to help!
you would have more control over it, you could customize it to your likings, and it would be more custom, Yeah Plugins others make are Awesome, but in this case, it looks like something customized to that server would be better. or at least in my opinion
“Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.” — Albert Einstein
"Never try to teach a pig to sing; it wastes your time and it annoys the pig." — Robert Heinlein