Meaty intro here.
http://fedoraproject.org/get-prerelease
What is the Alpha release?
The Alpha release contains all the exciting features of Fedora 17 in a form that anyone can help test. This testing, guided by the Fedora QA team, helps us target and identify bugs. When these bugs are fixed, we make a Beta release available. A Beta release is code-complete, and bears a very strong resemblance to the third and final release. The final release of Fedora 17 is due in early May.
We need your help to make Fedora 17 the best release yet, so please take a moment of your time to download and try out the Alpha and make sure the things that are important to you are working. If you find a bug, please report it -- every bug you uncover is a chance to improve the experience for millions of Fedora users worldwide. Together, we can make Fedora a rock-solid distribution. (Read down to the end of the announcement for more information on how to help.)
Condiments
This release of Fedora includes a variety of features both over and under the hood that show off the power and flexibility of the advancing state of free software. Examples include:
SEE FEATURE LIST, PICK FEATURES AND STICK HERE THAT ARE AWESOME AND LOOK LIKE THEY ARE LIKELY TO HAPPEN
These and many other improvements provide a wide and solid base for future Fedora releases. This release increases the range of possibilities for developers and helps Fedora to maintain its position at the leading edge of free and open source technology.
A more complete list and details of each new cited feature is available here:
http://fedoraproject.org/wiki/Releases/17/FeatureList
We also have nightly composes of alternate spins available here:
http://dl.fedoraproject.org/pub/alt/nightly-composes/
Issues and Details
For more information including common and known bugs, tips on how to report bugs, and the official release schedule, please refer to the release notes:
http://fedoraproject.org/wiki/Fedora_17_Alpha_release_notes
A shorter list of common bugs can be found here: https://fedoraproject.org/wiki/Common_F17_bugs
Contributing
Bug reports are helpful, especially for Alpha. If you encounter any issues please report them and help make this release of Fedora the best ever.
Thank you, and we hope to see you in the Fedora project!