I've been asked to research on adding a second app server to our farm.  Our current farm has two WFE that are load balanced and we have one app server and clustered SQL backend.  I've been asked to find out if its possible to add a second app server to our current environment to have full redundancy at each layer.  We don't have indexing server in our current farm.  The new server will serve as another application server.  Is it possible to do that?  If so, could you please point me in the right direction.

Thanks in advance for any input.

Rinu