Does anyone know of a free banner designer download or graphic software that could be used to design a banner or button.

not free. but a very good tool :

bannermakerpro

also might want to try

flamingtext.com

cooltext.com

for designing buttons or headings.

also try addesigner.com

u get to make free banner ads of various shapes. with the only limitation being there text added to ur banner. its free though