Is there a lightweight desktop application to connect to an Exchange server to just get mail? Ideally, the app would be free.
I am looking to replace Outlook for something that loads quicker and takes up less memory, etc.
I think you can use just about any mail clients to connect to Exchange and utilize POP3 or IMAP, but I don't know if you would get the full array of Exchange features.
Exchange provides IMAP access to a nice client, Mozilla Thunderbird. It even has a calendar plugin, lightning (not directly usable with exchange).
You can connect to Exchange using POP and IMAP, so therefore you can use any mail client. I use Apple Mail on my Mac personally and still use Outlook on Windows, but I also use Thunderbird on occasion.
If you want something completely free and have access to Exchange from the outside you can also use Outlook Web Access.
You could go for Gmail and POP into your Exchange server. ;)
This looks promising: http://www.emclient.com/, according to the website, it has calendar and contacts support.
I don't know the memory usage of this, but Zimbra Desktop
If your Exchange server has OWA/Webmail access, you can use the OWA plugin.
Just use the web access on the Exchange server.