I just recently switched to using Gmail as my universal e-mail for manageability purposes, which means (1) I can now send e-mail using my Yahoo! or Hotmail account within Gmail and (2) All my e-mails in Yahoo! and Hotmail is now archived in my Gmail account.
I was able to accomplish #1 easily by adding POP accounts, but only stumbled on the importing of mail and contacts today. When I did, I was happy and relieved, so sharing this info, as others may benefit from it.