Currently Being ModeratedFeb 11, 2013 8:08 AM (in response to James Wittmer)
Not directly, no. You should be able to move messages from your ISP's mail server to GMail within Mail on your iMac, though. Assuming you have both accounts set up in Mail, just select the messages you want to move and drag them to a mailbox associated with the GMail account. Make sure to let Mail have plenty of time to move the messages, as this can be a slow process with a large number of messages.
Currently Being ModeratedFeb 11, 2013 8:09 AM (in response to James Wittmer)
no, but you can have multiple different email accounts for Mail.
For instance I have icloud and gmail setup (through MS exchange so I can get push notifications).
I can see both just fine and when I go to the "inbox" folder, they are then merged together in on unified inbox.
Hope this helps.