Hi, Fabio...
As Bonnie stated, table variables only exist for the scope of the SP. They have the same general scope as any other variable – they are automatically cleared at the end of a procedure or function.
Unless there's something I'm not aware of, a table variable can't be released before the end of the procedure.
The following is an excellent link from Microsoft on table variables...
http://support.microsoft.com/default.aspx?scid=kb;en-us;305977Kevin