content page not the same font size on different browsers

Hi I need help. My website is http://www.im4b.com/answerbayarea/ and I want the font sizes the same for browsers Firefox and Internet Explorer. The font size in Internet Explorer is bigger than in Firefox. I already tried looking for the CSS in the options but I cannot find it. The text "Answer Bay Area is a full service telemessaging call center located in Tampa, Florida. We take the time to get to know you and your business. Our goal is to provide you with the most comprehensive, personal and competitively priced service in the industry." is using the <H2> tag. See attachments

Thanks