If the user agent string contains "SV1", Internet Explorer is in SP2.
PHP Code:
var g_fIsSP2 = false;
function browserVersion()
{
g_fIsSP2 = (window.navigator.userAgent.indexOf("SV1") != -1);
if (g_fIsSP2)
{
//This browser is Internet Explorer in SP2.
}
else
{
//This browser is not Internet Explorer in SP2.
}
}