BuddyPress.org

@gnattybumpo sounds like you are almost there. Your domain has to be setup for wildcard subdomains. If you don’t have access to DNS and your apache configuration file you’ll have to ask your hosting provider to make the changes for you. Here’s what the inimitable Matt has to say about this:

Wildcard DNS and Sub Domains

More than you ever want to know is at google search ‘dns wildcard subdomain’.