gnarf

No IE Welcome can react to a Visitor using Microsoft IE (Internet Explorer) of a specified Version. You can
<ol>
<li>Slide Down a Infoscreen (changeable CSS Style) where the User is informed that he should update his browser. All Texts and update Links are defineable in admin menu. No Popup is used, so no chance fpr Popup blockers. You can define a time where the Infowindow hides again automatically.</li>
</ol>
and / or
<ol>
<li>You can use a different WordPress Theme for these users. It can be a Theme that is optmized for IE, or a Theme where you suggest the user to Update / Cange Browser and so on. </li>
</ol>
For Users not affected by the Plugin the source code is not changed. So the Plugin is highly performant and a non IE User doesnt notice the use of the plugin at all.
Easy Installation and configuration.
Also visit the <a href="http://wordpress.losmuchachos.at/no_ie_welcome" title="Plugin Page" rel="nofollow ugc">PluginPage</a>.

No IE Welcome

No IE Welcome allows you to inform Vistors of a specified IE Version to Update their Browser. Also a different Theme can be used for these Visitors.

Vinnie

This plugin includes the <code>unitpngfix.js</code> javascript file if the browser is IE6 or lower. In plain words, it implements the solution for the PNG trasparency provided by Unit Interactive Labs (http://labs.unitinteractive.com/unitpngfix.php). It works on img objects and background-image attributes.
<h3>License</h3>
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. 
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. 
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place – Suite 330, Boston, MA 02111-1307, USA.

Wp-UnitPNGfix

This plugin includes the unitpngfix.js javascript file if the browser is IE6 or lower. In plain words, it implements the solution for the PNG traspare …

No IE Welcome vs Wp-UnitPNGfix