Ok Ladies and Gentleman, you all have waited for this links.
Here a the link for the Windows XP Service Pack I from the Microsoft Servers:
Download Win XP SP1 englisha>
Download WinXP SP1 german

The link goes to the Microsoft Premier Support Site but it is not password protected so than anybody can download it officialy.
We will see how long.

Big thanks goes to Malti over @ Planet-XP and ActiveWin for the links. Update:Look like microsoft has dropped the file. So we have to wait ;-)