I have a page that functions fine like this

<%
            YouTube youtube = new YouTube();
            youtube.DeveloperID = ConfigurationManager.AppSettings["DeveloperID"];
            Video[] videos = youtube.GetTaggedVideos("Beginner Guitar Lessons");
            for (int i = 0; i < videos.Length; i++) {
                %>
                <a href="GetVideo.aspx?VideoID=<%=videos[i].VideoID %>"><%=videos[i].Title %><br /><img src="<%=videos[i].ThumbnailUrl %>" alt="<%=videos[i].Title %>"/></a><br /><br />http://www.youtube.com/watch?v<%=videos[i].VideoID %><br />
                <iframe src="http://rcm.amazon.com/e/cm?t=blabla-20&o=1&p=9&l=st1&mode=books&search=yo%20mama&fc1=000000&lt1=&lc1=3366FF&bg1=FFFFFF&f=ifr" marginwidth="0" marginheight="0" width="180" height="150" border="0" frameborder="0" style="border:none;" scrolling="no"></iframe><br />
                <%
            }
        %>

now, I want to add an if statement in that so that the ad shows only after every third video like this

 <%
            YouTube youtube = new YouTube();
            youtube.DeveloperID = ConfigurationManager.AppSettings["DeveloperID"];
            Video[] videos = youtube.GetTaggedVideos("Beginner Guitar Lessons");
            for (int i = 0; i < videos.Length; i++) {
                %>
                <a href="GetVideo.aspx?VideoID=<%=videos[i].VideoID %>"><%=videos[i].Title %><br /><img src="<%=videos[i].ThumbnailUrl %>" alt="<%=videos[i].Title %>"/></a><br />copy/paste into RewindRewind<br />http://www.youtube.com/watch?v<%=videos[i].VideoID %><br />
                <%if(i=3){ %>
                <iframe src="http://rcm.amazon.com/e/cm?t=pilatesforpre-20&o=1&p=9&l=st1&mode=books&search=yo%20mama&fc1=000000&lt1=&lc1=3366FF&bg1=FFFFFF&f=ifr" marginwidth="0" marginheight="0" width="180" height="150" border="0" frameborder="0" style="border:none;" scrolling="no"></iframe><br />
                <%
                      }
            }
        %>

I get all kinds of errors that have nothing to do with that page in particular.  Any ideas? 

if(i=3) should change it to

if(i ==3)

It need double  = in C#

you're the man!  thanks alot.  the error system in web developer is a piece of *** though... why didn't it point me in that direction?  Instead it bitched about 9 other things that have nothing to do with that.