Making a profile field format into a link

[pjkcards]

Hello,
While registering, I want users to have a field that states this:
Enter your WCA profile code here (if available):
[example: for http://www.worldcubeassociation.org/...p?i=1234ABCD12, the profile code would be "1234ABCD12"]

When the user inputs the profile code, I want it to format into a link which I can put below the Avatars called "WCA Profile" (and that links goes to the WCA profile, such as the link shown above). I want the link to appear in the "Public Profile", as well as underneath the avatar by every post that person makes. How would I go about this?

Thanks.