If this is in the manual I did not see it.
Under the phone where you have the quick keys, you can assign them a name from your contacts that you call most.
I had a quick contact for each persons numbers such as cell, home, & work. The other day I stumbled across a feature that will let you put the name and one number such as home, you can highlight that name then press the spacebar and it will show you the other numbers that you have saved in your contacts for that person.
Maybe everyone already knows this option if you had a 650 but I moved up from a Sony Clie' and so far I'm lovin this phone.
