Try reading about POP3, IMAP protocol
Here is the visual studio example and once you can read the email you can check the server based on mail date and select the latest one
http://archive.msdn.microsoft.com/CSharpGmail
Here is the code:
// Create the object and get the feed
RC.Gmail.GmailAtomFeed gmailFeed = new RC.Gmail.GmailAtomFeed("username", "password");
gmailFeed.GetFeed();
// Access the feeds XmlDocument
XmlDocument myXml = gmailFeed.FeedXml
// Access the raw feed as a string
string feedString = gmailFeed.RawFeed
// Access the feed through the object
string feedTitle = gmailFeed.Title;
string feedTagline = gmailFeed.Message;
DateTime feedModified = gmailFeed.Modified;
//Get the entries
for(int i = 0; i < gmailFeed.FeedEntries.Count; i++) {
entryAuthorName = gmailFeed.FeedEntries[i].FromName;
entryAuthorEmail = gmailFeed.FeedEntries[i].FromEmail;
entryTitle = gmailFeed.FeedEntries[i].Subject;
entrySummary = gmailFeed.FeedEntries[i].Summary;
entryIssuedDate = gmailFeed.FeedEntries[i].Received;
entryId = gmailFeed.FeedEntries[i].Id;
}