If you need to use something like a stored procedure, you need to write something that stores SQL in a database table and a wrapper function to retrieve and execute it. But you won't benefit from the same advantages a SQL Server stored procedure has (such as being precompiled and parsed).
edit: I don't think this is a planned addition to MySQL in version N (where N is an unknown value). Heck, we're still waiting for sub-selects (though we can get by without 'em).
Sub-selects tend to make for sloppy and lazy SQL statements and can almost always be worked around using tight SQL or temporary tables. They're also a good way to slow down a query and MySQL takes pride in its speed. Probably why they're low-priority.