We mainly use Mitel 5340e phones and some users would like to be able to access and configure the keys and such from their computers. My research leads me to believe they can do this using the web configuration tool, however I am unable to get a webpage to display when you try to access the phones IP address.
Also I have 1 or 2 users that wish to use their desk phone through their computer headset. Is this possible? Would MiVoice or MiCollab be needed?
What do you mean "web configuration tool"? There is a way to log into a user account on the 3300 (MCD) controller and edit buttons, but not into the phone itself with the exception if they are in SIP mode, there is SOME configuration that can be done but it is pretty much just speed dials.
A computer headset, meaning a softphone? MiCollab can do that, or you can look at SIP softphone's like Counterpath's Bria.