ZoomPerfect is the name of the product. For IE8, IE7, and IE6.
ZoomPerfect turns Internet Explorer's Text Size menu into a Text Zoom an/or
Style-Switcher; enables IE to size and resize text set in pixels; detect and
modify Zoom levels; and more.
ZoomPerfect gives designers, developers, and webmasters greater freedom and
control over font-size without sacrificing the end-user's ability to adjust
the size of text in Internet Explorer.
It's in preview awaiting a solid Beta of IE8, check it out and sign up for
updates until the final release.