Colleges do not have the legal right to ask for your social security number as part of the application process --and you do not have to provide it to them. I would suggest that you just email all the colleges, tell them that you mistakenly gave them an erroneous social security number,and ask them to delete it from your file. Do NOT give them another – again, at this point they do not need it and it is mistake for you to provide it, for security reasons. (More than one school has had computers with student records compromised).
The financial aid office will have the numbers they need when the FAFSA is transmitted to them, and after you enroll in college, if you get a campus job or work-study – they will need the standard employment forms completed. But until then, you should not be giving that number out.