Or use the fetchmail feature already present in webmail and download your yahoo, gmail, other external mail accounts to webmail.
The only issue you have is mail will only be downloaded when you login to webmail, if you set it up that way, or when you manually fetch it from webmail, instead of possibly being downloaded in the background if that is what the dungog product does.
I currently use the fetchmail feature to download my gmail using the imap over ssl option.
John