The way I am currently doing this is by creating an Excel add-in. To do this, place your macros and forms into a new, empty Excel workbook and save as a .xlam document.
To use the macros, open the your Excel file and the add-in. To open the add-in automatically, save it to "C:\Program Files\Microsoft Office\Office12\XLSTART" (Vista).
You can even create a custom ribbon for your add-in using the Custom UI Editor for Microsoft Office http://msdn.microsoft.com/en-us/library/office/ee691832(v=office.14).aspx (The download link is at the end of the instructions)