The popular InstantUpgrade plugin has just become much easier to use! It now allows file transfers via an FTP account. Using InstantUpgrade now means simply to activate it and to enter the FTP account data. After that, you're ready to go -- Upgrading WordPress takes no longer than 10 seconds.
However, the new features of the plugin have to be tested on a variaty of hosts before we can remove the beta badge. So, if you are an experienced user and want to help improving a really great plugin, please visit the plugin's page.
(The older, but extensively tested version 0.2 is also available.)