N95 Mail for Exchange
Describes how to get mail for exchange ( a nokia app) running on the N95
First install 1.3.1 and enter all your settings, and do a full sync.
Now update to 1.5.0, the reason for this is that once 1.5.0 is installed non of the settings can be changed.
I am yet to give this a go on my N95 8GB, but will post an update once I have.
UPDATE: Download version 2.5.5 here