The Active Directory UserMod Assistant is an awesome application for your end users to change their own AD profile data, such as telephone number or address. It's a free solution, and it's built on HTML and VBScript - so all the core requirements should be on your user's workstations. In addition, the program is not compiled, allowing easy editing. For example, we put extensions in the 'Business' telephone number field, and don't want to validate it.
I'm deploying it via shortcut to a shared folder (The shortcut is autocreated on the user's desktop if it doesn't exist on login), so users who need VPN access can add their mobile number(s) for use with Phone Factor.
Note - There may be Security Issues when running the application from a share that is not in your Trusted Sites.