T-Mobile’s Sidekick celebrates its first birthday, and Cory Doctorow is plenty excited about the new features that have been added to it, so much so that he’s considering not ditching it even though his one-year contract is up. At least not until number-portability kicks in in November, that is, and he can switch providers and take his number with him. Among the improvements that Danger (the maker of the Sidekick) has made are the ability to cut and paste, a download manager, support for Java, extra features for AOL Instant Messenger, and better menu layouts.