301ing with ASP.NET

You could put this in your code-behind pages or even your global.asax file.

string oldPath =HttpContext.Current.Request.Url.PathAndQuery;
string newUrl = "http://www.seocactus.com"+oldPath;

Response.Clear();
Response.Status = "301 Moved Permanently";
Response.AddHeader("Location", newUrl);
Response.End();