Web site to track a team's training distance???

Hi all,

Some friends of mine have just gotten together, and we've committed to running 100km (600mi) next year.  So we want a web site where each of us can log our miles every day, on our way to 1000km.  The web site would allow us to create a group, add our distance, and see each other's progress.  Some social features would be great, too, but the main feature we want is to track our miles -- altogether but on one web site.

I haven't found anything like this.  Does anyone know of anything??

Thanks so much!!