Mail sent from gmail is always instant and mail from hotmail/yahoo etc is always instant to and from gmail. I think the issue is usually with your "webmail" not forwarding the mail quickly.

I experience this with my "domain email" that i have setup in gmail. So "[email protected]" for example. If you send mail there its available instantly if i login to a webmail access point like my hosting accounts cPanel (where i can use squirrel mail etc to view mail)...but it takes forever to show up at gmail.