If you signed up for the XPe Feature Pack then you should have gotten your invite via email by now. If you haven't signed up yet, its now a public beta. Just follow the instructions (Read More to find them), login and download the ISO image.
Announcing "Feature Pack 2007" for XP Embedded - the team has been extremely busy the last 4 months working on a feature pack for XP Embedded and we're just about ready to loop you into what we've been doing by giving you early access to the product in the form of a Technology Preview (not quite a Beta). Among our biggest goals in this Feature Pack are to improve the developer's experience and to enable new capabilities and Microsoft technologies on your embedded device.
1) Visit the Microsoft Connect Web site (https://connect.microsoft.com).
2) Click Invitations on the Connect menu.
3) You will need to sign in using a valid Windows Live ID before you can continue to the Invitations page.
4) Enter your Invitation ID in the box. Your invitation ID is: 123-BC7M-6GVK
5) Click Go.
6) If you have not previously registered with Microsoft Connect, you might be required to register before you continue with the invitation process.
7) You will then be asked to complete a User Profile survey for the program.