Convert MS SQL 7

I have inherited an ASP application that used MS SQL 7 for a backend DB.The original developer did an excellent job of commenting his work and the applications works fine as is. However, due to licnsing costs,the company is considering moving the application backend to MySQL.

I have looked at the DB structure and it has nothing extreneous other than FOREIGN KEYS. I have heard that MySQL does not support FOREIGN KEYS or Stored procedures.How do I get around the FOREIGN KEY support issue in MySQL?Other than changing my connection strings, if and when I do get the DB end working,do I need to redo the codes?I would like to keep the codes as is and simply redo the interface.In general what should I expect?

The Application was at the initial stages when the company changed course,so they don't mind losing what little data they have in the existing MS SQL 7 db,BUT the table structure must be kept as designed in MS SQL.