I think you are referring to "Host mail aggregation" - means: AOL will pull mail from external email accounts and store it within your account. This is a different concept then Desktop Mail software, which is able to connect to any mail account directly.
In any case: Short answer is yes. We are working on providing this feature.
Shotterm: You can forward mails from other accounts to your AOL account. We will provide a new feature where you can send mail with any email address in the near future.
