Enabling Macros

Is it possible to automatically enable macros..

In MSExcel 2003 I guess we can attach a digital Signature to a macro.. but what if the digital signature is not present..

I want to do it in MS Excel 2007 but there is no digital signature present..

From the help: You can obtain a digital certificate from a commercial certification authority, such as VeriSign, Inc., or from your internal security administrator or Information Technology (IT) professional. Or, you can create a digital signature yourself using the Selfcert.exe tool.

Thanks Kenneth