With the release of Mac OS X 10.1, some have been hoping to lay their hands on a copy of the updated developer tools. Those people will be pleased to learn that Apple has indeed now released the "Mac OS X version 10.1 Developer Tools" for download. One can download said tools by logging in to the Apple Developer Connect Web site. It requires a free account, but itis easy to get set up.
Once logged in, click on Download Software, where you will find the latest developer tools for Mac OS X. The description provided on the download page says it best:
A disk image (.dmg) of the Developer Tools 10.1 CD. This image contains the Developer meta-package used to install the Developer Tools on top of a Mac OS X 10.1 system. Requires: Mac OS X version 10.1
The disk image in its entirety is 187.1 MB.