check NEW pop mails

I have my own pop client, for which i used winsock.
I want to run this client in the background and check mails at regular interval (say 2 min or 5 mins).

I am not downloading any mails from this client - Just reading from the maail server.

How can I get an alert for New messages in always connected mode and in re-connect mode? Is there any command in POP to assist this? (I cudnt find any in the docs that I have)

Secondly, I want to use APOP. Is it a good way or can I use any other means to encrypt the pass over network send?

POP3 has very few commands. But I thought that one of them was how many un-read messages there are. If this number is different from the last time, then a new message must have arrived.

POP3 expects to receive a password in clear text. There may be implementations of it in certain places that allow SSL encrypted passwords to be sent - but that would be outside POP3, and be a part of the network implementation.

I don't think that there is an "always connected mode" for POP3. You enter a sign-on, get a list of un-read e-mails, down-laod those e-mails, delete those e-mails and sign off. I suppose if the sign-off is delayed by 10 minutes, then you are "always connected" for those 10 minutes. But POP3 is not clever enough to do anything other than respond to your commands.