Querystring values should always be URLEncode, either by:
C# url.aspx?name=<%= HttpContext.Current.Server.UrlEncode("my & name"); %>
umbraco.library in xslt: url.aspx?name=<xsl:value-of select="umbraco.library.UrlEncode('my & name')" />
javascript: var url = "url.aspx?name=" + encodeURIComponent("my & name");
If would be best if you could use <form method="get"> since it ensures Querystring values will be URLEncoded
CPalm,
www.cpalm.dk