"Request Access" Feature in MOSS 2007
By default the request access feature is  enabled for all the site collection and the reply-to address is set to the e-mail address of the  user who entered the SMTP server name. If you want to  use a different e-mail address, you can specify a different individual or group  e-mail account to receive access requests by the foll way:
 Home > Site Actions > Site  Settings > Modify All settings > Advanced Permissions > Select Settings  > Access Requests>change the email id you want them to recieve these  emails.
 If you want to turn down the feature,  uncheck the box and say "ok"
 
 
Comments
Happy New Year !
Mazeltov