Should you be installing IE8? I have answered this previously and my feelings have not changed and this is because Windows 7 comes with IE8, you simply don't have to use it and can do a pretty good job of turning it off, but it is better to have it installed and not being used then leaving the older IE7 (or IE6 yikes!)=
Here is where you can get it directly.
Direct Download Links to Internet Explorer 8 (IE8) Setup Installer
IE8 for Windows XP 32-bit Edition: IE8-WindowsXP-x86-ENU.exe
IE8 for Windows Server 2003 32-bit Edition: IE8-WindowsServer2003-x86-ENU.exe
IE8 for Windows Server 2003 or Windows XP Professional 64-bit Edition: IE8-WindowsServer2003-x64-ENU.exe
IE8 for Windows Vista and Windows Server 2008 32-bit Edition: IE8-WindowsVista-x86-ENU.exe
IE8 for Windows Vista or Windows Server 2008 64-bit Edition: IE8-WindowsVista-x64-ENU.exe
Starting from IE7, and similar in IE8, installation of Internet Explorer 8 no longer requires WGA genuine Windows validatoon. Microsoft also provides a few documents for end users, developers, IT professionals, businesses and enterprises to make better use of IE8.