Squirrelmail, Automated Signup

I'm looking for someone who can help me automate a branded version of Squirrelmail. The result should be comparable to hotmail or gmail, allowing a user to sign up by choosing a username, and they get an inbox for email address username at mydomain.com. the script should automatically create space for the user on my server at [login to view URL] with webmail being accessible at [login to view URL] (Please ignore the budget pricing, I've only chosen because I must choose a price. If it's more or if it's less just place your honest pricing...)