I am running Exchange 2010 on Server 2008. We have a number of mailboxes of ex-employees that we want to keep for reference purposes, but they are cluttering up my Management Console. I wanted to know if/how I can move the mailboxes to a different location and/or archive them to get them off my Management Console, but still have access if needed.

You can do a full backup on Exch and then just delete the mailboxes and user accounts. This will clear up your MC. However, if you wanted to to retrieve data from the mailboxes then you would have to do a restore or reconnect the mailbox to a user (depending on your rentensions period). You can keep your retension period so that mailb oxes arent deleted but that would chew up your disk space. In your MC I'd probably just use a filter and look for what you're after rather than trying to get rid of accounts to clear the clutter. You can archive (exch 2010 SP1) but this wont resolve your issue with the MC, You would still see them. If you want to get rid, you could export the mailbox data to PST and then back these up and/or put them on a net share for refernce then delete the mailboxes/users. Sukh