We have been planning to flag a text field as holding a URL and then allowing to click on the values, but we do not currently have that.
You can launch a URL using a script though, so if what you want is to have a component that you would click and it would open a web browser with a fixed URL, you can have that:
// $reference: System.dll
static Manifold.Context Manifold;
static void Main()
string url = "http://www.manifold.net";
System.Diagnostics.Process p = new System.Diagnostics.Process();
p.StartInfo.FileName = url;
p.StartInfo.UseShellExecute = true;
Hope this helps.