Custom "From" addresses in Gmail

I don't know if this is a recent feature in Gmail or not, but Gmail has added the ability to change the "From:" address when using Gmail.

This makes Gmail a lot more useful for me. I love the Gmail interface, but I often want to send mail from my corporate account or my other personal account, and that means using a number of different email programs to manage my mail. I may switch over the Gmail for all my email needs now.