Linking two projects
You can always use Response.Redirect()
to redirect the user to any location available on the Internet.
If both projects are configured as websites (i.e. they are accessible via virtual directories), you can use this method to perform a redirect. Without additional information, it is difficult to solve the problems you might face with this simple procedure.
Note that you won't be able to share state information between two apps (at least not straightforward!)
source to share
From the information you give in your question, I am assuming that you want to navigate from a "module" in one project to a "module" in another project, page, or control on a page ... The way to do this is to make a url for modules configurable. So you can go to modules like this
Response.Redirect(ConfigurablePropertyName);
Or on the client like this:
<a href='<%= this.ConfigurablePropertyName %>' >Click me</a>
Hope it helps.