User roles on registration

Hey Guys,
do you have any idea how we can integrate a dropdown / radio button in the registration part of the form to allow users to choose their roles? For example, I have a job listing site – and it would be great to have the option for users to choose either “Employer” or “Looking for a job” and seperate the two.

And bonus points if they can change this later on through tehir account – but thats not immediately important.

Cheers,