How to install iOS5 after first downloading it in iTunes?

[Jusfer]

So far, I only downloaded iOS5 in iTunes. After the download, I saw it listed in the library, but later, I could not find it again.

So, where is it filed, and how do I install it on the phone, without having to go through the lengthy download again?

 

[Helmsy67]

you should be able to just plug the phone up and click update