Please do note this is BETA keys, not for trial, not for RTM. This should not be used with any implementation. I leave this post here just for record, nothing more. [11/18/2010]
In case you can’t find it on download page after registration page:
SharePoint Server 2010 Beta(Enterprise Client Access License features) product key:
Both keys can be used. Feel free to post it elsewhere!
EDIT: The second key is a wrong one. Thanks to Olivier Brin to point it out. That key is for search server trial. Please use the first one during beta period, we will also update download center to remove the second one.