Web Mail and Messenger Services

I am looking to develop a web mail service connected with its' own messenger system just like Hotmail and Gmail. Please make sure you have good understanding of such a requirement of have some sort of a previous experience in this field. I am also look for some sort of an advice from you to tell me whats needed in terms of infrastructure (hardware etc.) to build up the whole business module. ## Deliverables My Requirements reside on having a GMAIL clone and MSN Messenger close both connected together exactly like hotmail works. Please provide Time and Money needed. Additional to this, please recommend that hardware specs we need, how many Dedicated Server, how many mail server, web server, backup server etc... do we need load balancers, do we need firewalls? etc. Thanks