This post is more than 2 years old.
This blog post is mostly for me so I don't forget, but here is an excellent tool for migrating from SQL Server to MySQL: MSSQL2MySQL. The only drawback is that you need MS Office or VB installed to run the script. I still have MS Office on my desktop, but I don't use it anymore. I'm completely on OpenOffice now. (Except on the Mac - I'm still using Office there till OpenOffice for the Mac gets improved.)