How to disable mysite functionality in SharePoint

My site functionality could be enabled / disabled through Shared Services Providers (SSP)

Navigate to  Central administration   select your Shared Services Provider 

Navigate to User Profiles and My Sites   > Personalization services permissions 

 Unselect  "create personal site" (Like shown below)

 use personal features allows users to use "My Links"  functionality, you can also disable it if you desire.

Create personal site
Use personal features
Manage user profiles
Manage audiences
Manage permissions
Manage usage analytics