For a while now I have had 3 Oracle Homes on my Laptop (Database, 10gIDS and 10gBI Tools) and several more on my server at home. It annoyed me that every visit to a new client site requried configuring multiple tnsname entries in all the Client Side apps.
A collegue at work demonstrated how to centrally manage your tnsnames so that all client apps use the same file.
Simply save your tnsnames and sqlnet files into a directory on your server (d:\My Documents\TNSNAMES)
Change the tnsnames and sqlnet entries in all the clients to:
ifile = d:\My Documents\TNSNAMES\tnsnames.ora
ifile= D:\My Documents\TNSNAMES\sqlnet.ora
And there you go, any changes to the centrally manages tnsnames / sqlnet files will be visible by all client apps pointed to use them.