.Net Windows Service to monitor mailbox

I need to create a .Net windows service to monitor a mailbox and process attachments (if found) on the emails and then delete the email from the server.

I h开发者_运维技巧ave two questions I'd like your thoughts on:

1. POP3 or IMAP to connect to the mail server?
2. Which POP3/IMAP library should I use. At this stage we're just doing a proof of concept, so a free one would be my preference.

Cheers!

OK, after doing some more research I've gone with C#Mail (http://csharpmail.codeplex.com/). So far it seems to do the job pretty well.

EDIT: Ended up having some random problems with c#mail so we ended up purchasing Rebex Mail and it has worked wonderfully well.

1. What does the server support? You will want to support both in many cases. In general, IMAP is superior in functionality, and superior in containing many funny edge cases, especially with less than stellar servers.