Questions on the best way to set up an ASP.NET project?

I am developing a web project with the following general architecture


Business Entities
Data Access Layer
Business Layer Logic
Web UI (contains all Code Behind for the aspx pages)


There are also various ASP.NET web projects which all inherit from the WebUI class (they contain no cs code themselves the inheritance is
set through the "Inherits" attribute of the <%@ Page %> directive.


The bin directory of each application contains local copies of all dlls referenced throughout the chain as well as it's own dll (these codeless projects still produce a dll which, when viewed in reflector, looks as though it contains just a reference to mscorlib, a namespace called "-" and a class called "<Module>")

We are now up to about 10 of these ASP.NET applications and so if there is a change to the DAL that means we have to update about 10 different places (also often this doesn't happen meaning that some of the sites are running on older versions of the common code base)


One other piece of information that may be relevant is that because not all members of the team have the code in the same physical location on their machines we are using "project references" in visual studio rather than "file references"

I believe the GAC may be a solution to this but am concerned as to what effect it will have on development.

If I am using a GAC'd version of the components then does that mean that everytime I make a slight change to them on my development machine then I will need to strongly sign them and reinstall them into the GAC - or have I misunderstood?